CN114928342B - High isolation and low loss integrated passive micro duplexer and its application - Google Patents

Abstract

The invention relates to a high-isolation low-loss integrated passive miniature duplexer, which comprises a low-pass filter and a high-pass filter, wherein the low-pass filter comprises two inductors, four capacitors, two grounding blocks and two signal ports; the high-pass filter comprises five capacitors, two inductors, two grounding blocks and a signal port; the capacitors are metal-medium-metal capacitors, the inductors are annular inductors, and an air bridge structure formed by multiple layers of metals is arranged at the port of each annular inductor. The invention designs the low-pass filter and the high-pass filter through the combination of the annular inductor and the metal-medium-metal type capacitor, and designs the miniature duplexer through the combination of the low-pass filter and the high-pass filter, thereby realizing high-isolation communication based on the microwave device, realizing low-loss signal transmission at the working frequency, improving the performance of the duplexer and greatly reducing the size of the device.

Description

High isolation and low loss integrated passive micro duplexer and its application

Technical field

The invention relates to the field of microwave communication technology, and in particular, to a high isolation and low loss integrated passive micro-duplexer and its application.

Background technique

Electronic devices have become an indispensable part of people's daily lives, but with the increase in the types of electronic devices, a series of problems have also arisen. Different electronic devices have different operating frequencies, so they cannot share a common communication channel and can only establish a separate communication channel for each device, but this will greatly increase the communication cost. Therefore, in order to reduce communication costs, duplexers are often used to solve the above problems.

A duplexer is a passive device that can realize frequency division multiplexing. A duplexer is usually reciprocal, that is, the device itself has no concept of input or output. When the duplexer works, the frequencies on the two ports are multiplexed into one port. The signals on the two ports occupy disjoint frequency bands, so the signals on the two ports can coexist on the third port and will not interfere with each other and thus share a common communication channel through a duplexer. A duplexer generally multiplexes the frequency of two ports into one port, or it can be multiplexed into more than two ports. A three-port to one-port multiplexer is called a triplexer, and a four-port to one-port multiplexer is called a triplexer. The port's multiplexer is a quadplexer.

Currently, there are many types of duplexers used in mobile communications. Common ones include waveguide duplexers, coaxial duplexers, dielectric duplexers and SAW duplexers. Among them, the waveguide duplexer is the earliest duplexer used in the communication field and is widely used. However, it is large in size, high in cost and very difficult to tune. The coaxial duplexer has low power loss and is very practical. , but due to its large size, it is still difficult to apply in electronic equipment. Based on this shortcoming, an improved spiral coaxial duplexer has emerged, which greatly reduces the size. However, its quality factor Q value also increases decrease; the dielectric duplexer is composed of a dielectric filter. The dielectric constant of the dielectric material is dozens of times higher than that of the air medium. At the same time, it can be miniaturized and improve the performance of the duplexer. It is currently widely used; SAW duplexer It is a transducing passive bandpass filter made by utilizing the piezoelectric effect of the piezoelectric quartz crystal oscillator material and the physical properties of surface acoustic wave propagation. It can suppress high-order harmonics, image information, and emission of electronic equipment. It can eliminate interference from leakage signals and various parasitic clutter problems, and can achieve filtering of amplitude-frequency characteristics and phase-frequency characteristics with any required precision. Integrated passive micro-duplexer is a new technology, which has been widely used in the design of passive devices such as microwave sensors. Therefore, it is particularly important to design an integrated passive micro-duplexer with high isolation and low loss. important.

Contents of the invention

To this end, the technical problem to be solved by the present invention is to overcome the problems existing in the existing technology and propose a high isolation and low loss integrated passive micro-duplexer and its application, which uses a ring inductor and a metal-dielectric-metal capacitor. The combination of low-pass filter and high-pass filter is designed, and the micro-duplexer is designed through the combination of low-pass filter and high-pass filter, which realizes high-isolation communication based on microwave devices and can achieve low-loss signal transmission at the operating frequency. , while improving the performance of the duplexer, it greatly reduces the size of the device; it provides an effective solution for the application of micro-duplexers in duplex communications and helps to promote the application of micro-duplexers in duplex communications. Exploration and application in duplex communication.

In order to solve the above technical problems, the present invention provides a high isolation and low loss integrated passive micro-duplexer, including:

A low-pass filter including a first inductor, a second inductor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first signal port and a second signal port, the first inductor and the first capacitor In parallel, one end is connected to the first signal port, the other end is connected to the second capacitor and grounded, and the end connected to the second capacitor is also connected to one end of the second inductor and the third capacitor in parallel, and the second inductor and the third capacitor are connected in parallel. The other end of the fourth capacitor is connected to the ground, and the end of the fourth capacitor is connected to the second signal port;

A high-pass filter, which includes a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a third inductor, a fourth inductor and a third signal port, one end of the fifth capacitor is connected to the first signal port, the other end of which is connected to one end of the third inductor and the sixth capacitor connected in series, and the end of the third inductor and the sixth capacitor connected in series is simultaneously connected to one end of the seventh capacitor, and the other end of the seventh capacitor is connected to the fourth One end of the inductor and the eighth capacitor connected in series; and the end of the fourth inductor and the eighth capacitor connected in series is connected to one end of the ninth capacitor, and the other end of the ninth capacitor is connected to the third signal port, and the third inductor and the sixth capacitor are connected in series. The capacitor is connected in series and then connected to ground, and the fourth inductor and the eighth capacitor are connected in series and then connected to ground;

Wherein, the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the fifth capacitor, the sixth capacitor, the seventh capacitor, the eighth capacitor and the ninth capacitor are metal-dielectric-metal type capacitors; so The first inductor, the second inductor, the third inductor and the fourth inductor are all ring inductors.

In one embodiment of the present invention, an air bridge structure is provided at a port of the ring inductor, and the air bridge structure is composed of multiple layers of metal.

In one embodiment of the present invention, the ring inductor includes a ring metal line and a rectangular metal line. During production, gaps are formed at the intersections of the ring metal line and the rectangular metal line, and the first layer of metal is laid out on the ring metal line. , there is no change in the rectangular metal line, and then a second layer of metal is laid out on the ring metal line and all the ring metal lines are connected. There is no change in the rectangular metal line. At this point, a ring inductor with an air bridge structure is produced.

In one embodiment of the present invention, the metal-dielectric-metal capacitor includes a stacked first plate, a dielectric layer and a second plate.

In one embodiment of the present invention, when manufacturing the metal-dielectric-metal capacitor, a first layer of metal is first made, and a first rectangular port is made to connect the first layer of metal as the second plate. A layer of silicon nitride is made as a dielectric layer in the effective area of the plate, and a second layer of metal is made on the silicon nitride. At the same time, a second rectangular port is made to connect the second layer of metal as the first plate. At this point, the metal is produced - Dielectric-metallic capacitors.

In one embodiment of the present invention, the low-pass filter further includes a first ground block and a second ground block, and the ground terminal of the first inductor and the first capacitor connected in parallel is connected to the first ground block, The ground end of the parallel connection of the second inductor and the third capacitor is connected to the second ground block.

In one embodiment of the present invention, the high-pass filter further includes a third ground block and a fourth ground block. A third inductor and a sixth capacitor are connected in series and then connected to the third ground block. The fourth inductor and the sixth capacitor are connected in series to the third ground block. The eighth capacitor is connected in series and then connected to the fourth ground block.

In one embodiment of the present invention, the calculation formula of the inductance value in the low-pass filter is as follows:

ω _C =2πf _C

Among them, L represents the inductance, Ω _C represents the cut-off frequency, γ ₀ represents the impedance scaling factor, g represents the inductance value of the prototype series-parallel inductor, ω _C represents the angular cut-off frequency, Z ₀ represents the port impedance, and g ₀ represents the source conductance, f _C represents the operating frequency.

In one embodiment of the present invention, the calculation formula of the capacitance value in the low-pass filter is as follows:

ω _C =2πf _C

Among them, C represents the capacitance, Ω _C represents the cut-off frequency, g represents the capacitance value of the prototype series-parallel capacitor, γ ₀ represents the impedance scaling factor, ω _C represents the angular cut-off frequency, Z ₀ represents the port impedance, g ₀ represents the source conductance, f _C represents the operating frequency.

In one embodiment of the present invention, the calculation formula of the inductance value in the high-pass filter is as follows:

Among them, L represents the inductance, γ ₀ represents the impedance scaling factor, ω _C represents the angular cut-off frequency, Ω _C represents the cut-off frequency, and g represents the inductance value of the prototype parallel-series inductor.

In one embodiment of the present invention, the calculation formula of the capacitance value in the high-pass filter is as follows:

Among them, C represents the capacitance, Ω _C represents the cut-off frequency, γ ₀ represents the impedance scaling factor, ω _C represents the angular cut-off frequency, and g represents the capacitance value of the prototype parallel-series capacitor.

In addition, the present invention also provides an application of the above-mentioned high isolation and low loss integrated passive micro-duplexer in duplex communication.

The above technical solution of the present invention has the following advantages compared with the existing technology:

1. The present invention designs low-pass filters and high-pass filters through the combination of ring inductors and metal-dielectric-metal capacitors, designs micro-duplexers through the combination of low-pass filters and high-pass filters, and realizes microwave device-based High-isolation communication can achieve low-loss signal transmission at the operating frequency, which greatly reduces the size of the device while improving the performance of the duplexer;

2. The present invention provides an effective solution for the application of micro-duplexers in duplex communications, and helps to promote the exploration and application of micro-duplexers in duplex communications.

Description of drawings

In order to make the content of the present invention easier to understand clearly, the present invention will be described in further detail below based on specific embodiments of the present invention and in conjunction with the accompanying drawings.

Figure 1 is an equivalent circuit diagram of the integrated passive micro-duplexer of the present invention;

Figure 2 is a schematic plan view of the integrated passive micro-duplexer of the present invention;

Figure 3 is a partial structural schematic diagram of the integrated passive micro-duplexer of the present invention;

Figure 4 is an S-parameter test chart of the integrated passive micro-duplexer of the present invention;

Figure 5 is a schematic plan view of the low-pass filter of the present invention;

Figure 6 is an S-parameter test chart of the low-pass filter of the present invention;

Figure 7 is a schematic diagram of the planar layout of the high-pass filter of the present invention;

Figure 8 is an S-parameter test chart of the high-pass filter of the present invention.

The reference numbers are as follows: 1. Inductor; 2. Capacitor; 3. Ground block; 4. Signal port; 5. First plate; 6. Dielectric layer; 7. Second plate; 8. Air bridge structure.

Detailed ways

The present invention will be further described below in conjunction with the accompanying drawings and specific examples, so that those skilled in the art can better understand and implement the present invention, but the examples are not intended to limit the present invention.

Referring to Figures 1 to 3, an embodiment of the present invention provides a high-isolation, low-loss integrated passive micro-duplexer, which includes a low-pass filter and a high-pass filter. The low-pass filter includes two inductors 1, Four capacitors 2, two ground blocks 3 and two signal ports 4; the high-pass filter includes five capacitors 2, two inductors 1, two ground blocks 3 and one signal port 4; the capacitors 2 are all metal - The dielectric-metal type capacitor and the inductor 1 are both ring-shaped inductors, and an air bridge structure 8 composed of multiple layers of metal is provided at the port of the ring-shaped inductor.

Specifically, the inductors in the low-pass filter are marked as the first inductor L1 and the second inductor L2 from left to right, and the capacitors are marked as the first capacitor C1, the second capacitor C2, the third capacitor C3 and the third capacitor C3 from left to right. Four capacitors C4, the signal ports are recorded as the first signal port Port1 and the second signal port Port2 from left to right. The first inductor L1 and the first capacitor C1 are connected in parallel, one end of which is connected to the first signal port Port1, and the other end is connected to The second capacitor C2 is also connected to the first ground block, and the end connected to the second capacitor C2 is also connected to one end of the parallel connection of the second inductor L2 and the third capacitor C3, and the other end of the parallel connection of the second inductor L2 and the third capacitor C3. One end is connected to the fourth capacitor C4 and connected to the second ground block, and the end connected to the fourth capacitor C4 is also connected to the second signal port Port2; the inductors in the high-pass filter are sequentially recorded as the third inductor L3 and the fourth inductor L4, and the capacitor They are recorded as the fifth capacitor C5, the sixth capacitor C6, the seventh capacitor C7, the eighth capacitor C8 and the ninth capacitor C9 in sequence. One end of the fifth capacitor C5 is connected to the first signal port Port1, and the other end is connected to the third inductor. One end of L3 and the sixth capacitor C6 are connected in series, and the end of the third inductor L3 and the sixth capacitor C6 are connected in series to one end of the seventh capacitor C7, and the other end of the seventh capacitor C7 is connected to the fourth inductor L4 and One end of the eighth capacitor C8 connected in series; and the end of the fourth inductor L4 and the eighth capacitor C8 connected in series is connected to one end of the ninth capacitor C9, and the other end of the ninth capacitor C9 is connected to the third signal port Port3, and the third The inductor L3 and the sixth capacitor C6 are connected in series and connected to the third ground block. The fourth inductor L4 and the eighth capacitor C8 are connected in series and connected to the fourth ground block.

Wherein, the first capacitor C1, the second capacitor C2, the third capacitor C3, the fourth capacitor C4, the fifth capacitor C5, the sixth capacitor C6, the seventh capacitor C7, the eighth capacitor C8 and the ninth capacitor C9 are all Metal-dielectric-metal type capacitor 2; the first inductor L1, the second inductor L2, the third inductor L3 and the fourth inductor L4 are all ring-shaped inductors 1, and the port of the ring-shaped inductor 1 is provided with a multi-layer metal Air bridge structure 8.

The present invention designs a low-pass filter and a high-pass filter through the combination of the ring inductor 1 and the metal-dielectric-metal capacitor 2, and designs a micro-duplexer through the combination of the low-pass filter and the high-pass filter, thereby realizing microwave device-based High-isolation communication can achieve low-loss signal transmission at the operating frequency, which greatly reduces the size of the device while improving the performance of the duplexer.

The micro duplexer proposed in this embodiment uses the processing technology of integrated passive devices to design metal transmission lines, ring inductors 1, and metal-dielectric-metal capacitors 2, combined with the air bridge structure 8 and optimized parallel-series connections This method improves the integration of the duplexer and can reduce the size of the device to a great extent. It consists of a low-pass filter and a high-pass filter transformed from the elliptic function prototype filter. The elliptic function prototype low-pass filter The inductance and capacitance values of the filter can be determined by the following equations,

ω _C =2πf _C

Among them, L represents the inductance, C represents the capacitance, Ω _C represents the cut-off frequency, γ ₀ represents the impedance scale factor, g in the inductance formula represents the inductance value of the prototype series-parallel inductor, and g in the capacitance formula represents the prototype string- The capacitance value of the parallel capacitor, ω _C represents the angular cut-off frequency, Z ₀ represents the port impedance, g ₀ represents the source conductance, and f _C represents the operating frequency.

The inductor and capacitor values of the elliptic function prototype high-pass filter can be determined by the following equations,

Among them, L represents the inductance, C represents the capacitance, γ ₀ represents the impedance scale factor, ω _C represents the angular cut-off frequency, and Ω _C represents the cut-off frequency. The g in the inductance formula represents the inductance value of the prototype parallel-series inductor. Solve the capacitance formula The g in represents the capacitance value of the prototype parallel-series capacitor.

The schematic diagram of the plan layout of the micro duplexer is shown in Figure 2. The overall structure includes a low-pass filter and a high-pass filter. In the structure of the entire device, a resonant mode with a small number of ring inductors 1 is used to reduce the size of the device; In the structure of a single device, multi-layer metal is designed at the port of the ring inductor 1 to form an air bridge structure 8, which realizes a three-dimensional design of the device, reduces design errors, and provides new ideas for the three-dimensional overlapping design of the device. It is expected to further reduce the size of microwave passive components. The partial structural diagram of the integrated passive micro-duplexer is shown in Figure 3, which shows the air bridge structure 8 at the port of the ring inductor 1. The reason why the air bridge structure 8 is used at both ports is to control the ring inductor 1 Optimize the connection method in parallel with the metal-dielectric-metal type capacitor 2, connect the capacitor 2 inside the coil of the inductor 1, make full use of the space, shorten the length of the metal wire, reduce the local size of the low-pass filter, and then reduce the The size of the duplexer is reduced and the integration level of the duplexer is improved.

Figure 1 is an equivalent circuit diagram of the integrated passive micro-duplexer of the present invention. The low-pass filter is connected to the signal port Port1 and the signal port Port2. After the inductor L1 and the capacitor C1 are connected in parallel, one end is connected to the signal port Port1 and the other end is connected to the capacitor. C2 is grounded and connected to one end of the parallel connection of inductor L2 and capacitor C3. The other end of the parallel connection of inductor L2 and capacitor C3 is connected to capacitor C4 to ground and to signal port Port2. The high-pass filter connects signal port Port1 and signal port Port3. One end of the capacitor C5 is connected to the signal port Port1, the other end is connected to the inductor L3 and the capacitor C6 in series and then grounded, and at the same time connected to one end of the capacitor C7. The other end of the capacitor C7 is connected to the inductor L4 and the capacitor C8 in series and then grounded, and at the same time connected to one end of the capacitor C9. The other end of the capacitor C9 is connected to the signal port Port2. During operation, low-frequency signals communicate between signal ports 1 and 2, and high-frequency signals communicate between signal ports 1 and 3 without interfering with each other.

The S-parameter test chart of the integrated passive micro-duplexer of the present invention is shown in Figure 4. From the S-parameter test chart, it can be seen that at the frequencies of 0.9GHz and 1.8GHz, the insertion loss of the duplexer, namely S21 and S31, is very small, indicating that The communication performance at these two operating frequencies is very good, and almost all signals can pass through. At the same time, the return loss of the duplexer, S11, is relatively large, indicating that under these two operating frequencies, most signals can pass through the signal port Port2 and the signal port Port Port3, almost no signal returns to the signal port Port1, that is, the designed duplexer has low loss characteristics. The isolation degree of the duplexer, that is, S32, is relatively large, indicating that under these two operating frequencies, almost no signal passes between the signal port Port2 and the signal port Port3. During the design process of the duplexer, the low-pass filter was improved. , omitting a capacitor between the signal port Port1 and the low-pass filter, this can increase the isolation between the signal port Port2 and the signal port Port3, so that the two ports do not affect or interfere with each other, so that the two The device has the characteristics of high isolation.

The design method of the above low-pass filter is as follows:

In order to reduce design errors and facilitate circuit connection, the present invention designs an air bridge structure 8 for the internal interface of the coil of the toroidal inductor 1, and connects it to the outside of the coil without affecting the inductance of the toroidal inductor 1. This reduces the errors that may occur during use of the toroidal inductor 1.

The low-pass filter is connected to the signal port Port1 and the signal port Port2. After the inductor L1 and the capacitor C1 are connected in parallel, one end is connected to the signal port Port1, and the other end is connected to the capacitor C2 to ground. At the same time, the inductor L2 and the capacitor C3 are connected in parallel. The inductor L2 The other end connected in parallel with capacitor C3 is connected to capacitor C4 and grounded, and is connected to signal port Port2. The inductor L1 is composed of 6.375 turns of annular metal wires, with a single line width of 15 μm, a line spacing of 15 μm, an inner diameter of 50 μm, and an outer diameter of 230 μm. The inductor L2 is composed of 4.5 turns of annular metal wire, with a single line width of 15 μm, a line spacing of 15 μm, an inner diameter of 125 μm, and an outer diameter of 245 μm. The effective area of capacitor C1 is 25×25.158μm, the effective area of capacitor C2 is 200×83.438μm, the effective area of capacitor C3 is 25×72.982μm, the effective area of capacitor C4 is 100×92.099μm, the line width at both ends of the capacitor is equal is 20μm. A 100×100μm square is designed at the grounding point of capacitor C2 and capacitor C4 to facilitate grounding. The determination of the above values can improve the quality factor of the inductor and reduce the loss of the capacitor.

In the design of this low-pass filter, one of the capacitor grounding structures is omitted. Through this design, the isolation between signal port Port2 and signal port Port3 can be increased, the performance of the duplexer can be improved, and it can be applied to more complex applications. , in a more demanding environment. In order to solve the problem that the duplexer is too large, the present invention improves the parallel connection method of the capacitor 2 and the inductor 1 through the air bridge structure 8, and provides a connection where the capacitor 2 is designed in the blank area in the middle of the ring inductor 1 This way, the volume of the low-pass filter can be reduced by half while reducing the size of the duplexer.

Design method of ring inductor 1 and air bridge: first lay out a layer of 5μm metal on the gallium arsenide substrate where the ring inductor 1 is made, disconnect the intersection of the ring metal line and the rectangular metal line to form a gap, and then Only a layer of 3 μm metal is laid out on the ring metal line, and the rectangular metal line remains unchanged. Finally, a layer of 2 μm metal is laid out on the ring metal line and connects all the ring metal lines. The rectangular metal line remains unchanged. So far, there is The annular inductor 1 of the air bridge is designed. At the same time, this method is applicable to all shapes of annular inductors 1, not only circular, but also rectangular, square, polygonal, etc. can use this method. This design can reduce the size of the duplexer and provides a new connection method for the parallel connection of the toroidal inductor and the metal-dielectric-metal capacitor.

The design method of the above high-pass filter is as follows:

The high-pass filter is connected to the signal port Port1 and the signal port Port3. One end of the capacitor C5 is connected to the signal port Port1, and the other end is connected to the inductor L3 and capacitor C6 in series and then grounded. At the same time, it is connected to one end of the capacitor C7, and the other end of the capacitor C7 is connected to the inductor L4. Connect it in series with capacitor C8 and then connect it to ground. At the same time, connect one end of capacitor C9 and the other end of capacitor C9 to signal port Port2. The inductor L3 is composed of 3.25 turns of annular metal wires, with a single line width of 15 μm, a line spacing of 15 μm, an inner diameter of 100 μm, and an outer diameter of 190 μm. Inductor L4 is composed of 3.5 turns of annular metal wire, with a single line width of 15 μm, a line spacing of 15 μm, an inner diameter of 100 μm, and an outer diameter of 190 μm. The effective area of capacitor C5 is 56.267×100μm, the effective area of capacitor C6 is 235×223.572μm, the effective area of capacitor C7 is 50×67.608μm, the effective area of capacitor C8 is 200×137.56μm, and the effective area of capacitor C9 is 100 ×60.695μm, the line width at both ends of the capacitor is 20μm. A 100×100μm square is designed at the grounding point of capacitor C6 and capacitor C8 to facilitate grounding. The determination of the above values can improve the quality factor of the inductor and reduce the loss of the capacitor.

The design method of metal-dielectric-metal capacitor 2: first lay out a layer of 5 μm metal on the gallium arsenide substrate, and at the same time lay out a rectangular port connected together as the second plate 7 (lower plate) of capacitor 2, and then Next, a layer of silicon nitride is laid out in the effective area of the second plate 7 as the dielectric layer 6 of the capacitor 2. Finally, a layer of 5 μm metal is laid out on the silicon nitride, and a rectangular port is grown and connected together as the third layer of the capacitor 2. One plate 5 (upper plate), now the three-dimensional capacitor 2 with metal-dielectric-metal structure has been designed. At the same time, this method is suitable for all shapes of metal-dielectric-metal capacitors 2, not limited to rectangular, circular, This method can be used for rhombuses, polygons, etc.

The above-mentioned low-pass filter and high-pass filter can be combined to form the high-isolation low-loss integrated passive micro-duplexer proposed by the present invention. In the overall design, the width of the transmission line is 20 μm, and the width of each signal port is The size is 100×137.604μm. This size is calculated by the simulation software Advanced Design System 2020. This size can better match 50Ω, which facilitates the combination of the device with other devices and can be directly connected together. The resulting The error is very small and can be ignored.

In a preferred embodiment, Figure 5 shows a schematic plan view of the low-pass filter of the present invention. The low-pass filter includes two annular inductors 1, five metal-dielectric-metal capacitors 2, and three The structure of a ground block 3 and two signal ports 4 adopts a series-parallel resonance method, which can reduce the number of inductors in the circuit and thereby reduce the overall size of the low-pass filter. At the same time, the parallel capacitor 2 of the branch can be The transmission zero point ensures that a large series impedance is generated when resonating at high frequencies to prevent signal transmission.

The inductance value and capacitance value of the low-pass filter can be calculated and determined by the above equation. The omitted capacitor value in the low-pass filter is 3.46pF, capacitor C1: 0.23pF, capacitor C2: 5.71pF, capacitor C3: 0.64pF , capacitor C4: 3.11pF, inductor L1: 10.29nH, inductor L2: 9.1nH. In the plan layout diagram of Figure 5, the capacitor adopts a metal-dielectric-metal structure. The capacitor structure size omitted in the low-pass filter is 53×203μm. The inductor adopts a circular ring inductor structure. The line width and line The intervals are all 15μm. Preferably, these values can reduce the insertion loss of the low-pass filter and ensure that the signal passes as completely as possible; increase the return loss of the low-pass filter and minimize the return of the signal from the input port; and increase the isolation of the duplexer .

The frequency response results of the low-pass filter are shown in Figure 6. The transmission poles are 0.615GHz and 0.957GHz respectively, and the transmission zeros are 2.085GHz and 3.272GHz respectively. The positions of the transmission poles can ensure that the low-pass filter operates at a frequency of 0.9GHz. Normal operation, while transmitting zero points can prevent signal transmission at high frequencies. The low-pass filter can achieve a fifth-order low-pass frequency response with relatively good performance. The 0.9GHz frequency band is extremely widely used in radio electromagnetic wave communications and has been used since the original GSM communication system. From the 1G of wireless communications to the current 5G, and then to the future 6G, the frequency of radio electromagnetic waves used is constantly increasing, and the frequency band is constantly broadening, but the original band has always been used, so the low-pass filter It has great application prospects in the field of wireless electromagnetic wave communication. The low-pass filter can also be used to filter high-frequency noise signals from the circuit. When the signal passes through the low-pass filter, the high-frequency signal can be blocked and eliminated.

In a preferred embodiment, Figure 7 shows a schematic plan view of the high-pass filter of the present invention. The high-pass filter includes two annular inductors 1, five metal-dielectric-metal capacitors 2, two Ground block 3 and two signal ports 4. The design of the high-pass filter is obtained by the inverse transformation of the inductor 1 and capacitor 2 components in the low-pass filter structure. Therefore, in order to reduce the number of inductor 1 components in the circuit and reduce the size of the overall device, the circuit design adopts the combination- In the series resonance mode, after the transformation, five inductors 1 become two inductors 1. At the same time, the parallel structure of inductor 1 and capacitor 2 obtains the transmission zero point, ensuring that a large parallel impedance is generated during resonance at low frequencies to prevent signal transmission. Form a fifth-order elliptic function high-pass filter.

The inductance value and capacitance value of the high-pass filter can be calculated and determined by the above equation. The values of each component in the high-pass filter are as follows: capacitor C5: 1.95pF, capacitor C6: 28.99pF, capacitor C7: 1.18pF, capacitor C8: 10.59 pF, capacitor C9: 2.17pF, inductor L3: 4.1nH, inductor L4: 4.64nH. Optimizing these values can reduce the insertion loss of the high-pass filter and ensure that the signal passes as completely as possible; increase the return loss of the high-pass filter and minimize the return of the signal to the input port; optimize the performance of the transmission zero point and improve the duplex The isolation of the device.

The frequency response results of the high-pass filter are shown in Figure 8. The transmission poles are 1.569GHz and 2.435GHz respectively, and the transmission zeros are 0.462GHz and 0.718GHz respectively. The position of the transmission pole can ensure that the high-pass filter works normally at the frequency of 1.8GHz. At the same time, the transmission zero point can prevent signal transmission at low frequencies. The high-pass filter can achieve a fifth-order high-pass frequency response with high sensitivity and good performance. Wireless communication in the 1.8GHz frequency band plays a major role in the field of automated power distribution. Domestic radio frequency applications are mainly divided into three bands: 0.223-0.235GHz, 1.427-1.525GHz and 1.785-1.805GHz. Among them, 0.223-0.235GHz is used by power grid companies. 25kHz is a frequency point for data transmission; some frequency points in 1.427-1.525GHz are used as microwaves by some power grid companies; only some sporadic bands of 1.785-1.805GHz are used. The coverage range of the power wireless broadband private network is basically consistent with the power supply range of the 110kV substation, and a TD-LTE wireless communication network based on 1.8GHz has been built in China. It is the largest wireless broadband in the power industry, covering open spaces in dense urban areas and suburbs. Areas and emergency drill points and other scenarios. Therefore, the 1.8GHz high-pass filter with optimized performance has great application prospects in power wireless communication technology, and can further increase the regional coverage and improve the stability of power grid communication.

Corresponding to the above embodiments of the high isolation and low loss integrated passive micro duplexer, embodiments of the present invention also provide an application of a high isolation and low loss integrated passive micro duplexer in duplex communications.

In a preferred embodiment, the present invention uses integrated passive device processing technology to design a miniature fifth-order duplexer. The duplexer allows two-way (duplex) communication on a single path, in radar and radio communication systems. , which isolates the receiver from the transmitter while allowing them to share a common antenna, can function in many radio repeater systems, operating based on frequency, polarization or timing. The duplexer designed in the present invention can be composed of a fifth-order elliptic function low-pass filter and a fifth-order elliptic function high-pass filter to isolate the receiver and transmitter. The total circuit size is 2236×1966μm, the operating frequency is 0.9GHz and 1.8GHz, the insertion loss of the two operating frequency bands is 0.003dB and 0.001dB, the insertion loss is in the signal channel corresponding to the operating frequency, and the passband frequency point is suitable for the useful signal The loss, the smaller the loss, the smaller the fluctuation in the band and the easier it is for the signal to pass. The losses of this design are less than 0.01dB to achieve the goal of low loss; the isolation is 39.439dB and 43.197dB respectively. The isolation refers to the difference between the low-pass filter and The stopband attenuation of a high-pass filter is generally equivalent to the stopband attenuation in the receiving channel and transmitting channel of a duplexer. When the isolation is small, the signal will pass through the two channels. When the isolation is large, the signal will pass through the two channels. , the signal will only pass through its own channel. The isolation of this design is greater than 35dB, achieving the goal of high isolation, which can greatly improve the working efficiency of the duplexer. The present invention utilizes the processing technology of integrated passive devices to greatly reduce the size of passive devices. The combination of ring inductors and metal-dielectric-metal capacitors increases design accuracy and design flexibility, and has a stable structure and is not affected by the environment. It is smaller and realizes a three-dimensional design to a certain extent. It can be easily integrated with other devices through jumpers, which is beneficial to improving the integration of radio frequency circuits and increasing its performance.

When the integrated passive micro duplexer with high isolation and low loss proposed by the present invention is used in duplex communication, the present invention provides an effective solution for the application of the micro duplexer in duplex communication. Helps promote the exploration and application of micro-duplexers in duplex communications.

Obviously, the above-mentioned embodiments are only examples for clear explanation and are not intended to limit the implementation. For those of ordinary skill in the art, other changes or modifications may be made based on the above description. An exhaustive list of all implementations is neither necessary nor possible. The obvious changes or modifications derived therefrom are still within the protection scope of the present invention.

Claims (6)

1. A high isolation low loss integrated passive micro-duplexer, comprising:

the low-pass filter comprises a first inductor, a second inductor, a first capacitor, a second capacitor, a third capacitor, a fourth capacitor, a first signal port and a second signal port, wherein the first inductor and the first capacitor are connected in parallel, one end of the first inductor is connected with the first signal port, the other end of the first inductor is connected with the second capacitor and grounded, one end of the second capacitor is connected with one end of the second capacitor, which is connected with the second inductor and the third capacitor in parallel, the other end of the second capacitor is connected with the fourth capacitor and grounded, and the end of the second capacitor is connected with the fourth capacitor and the second signal port;

the high-pass filter comprises a fifth capacitor, a sixth capacitor, a seventh capacitor, an eighth capacitor, a ninth capacitor, a third inductor, a fourth inductor and a third signal port, wherein one end of the fifth capacitor is connected with the first signal port, the other end of the fifth capacitor is connected with one end of the third inductor and the sixth capacitor which are connected in series, the end of the third inductor and the end of the sixth capacitor which are connected in series are simultaneously connected with one end of the seventh capacitor, and the other end of the seventh capacitor is connected with one end of the fourth inductor and the eighth capacitor which are connected in series; the end of the fourth inductor and the eighth capacitor which are connected in series is connected with one end of the ninth capacitor, the other end of the ninth capacitor is connected with a third signal port, the third inductor and the sixth capacitor are connected in series and then grounded, and the fourth inductor and the eighth capacitor are connected in series and then grounded;

the first capacitor, the second capacitor, the third capacitor, the fourth capacitor, the fifth capacitor, the sixth capacitor, the seventh capacitor, the eighth capacitor and the ninth capacitor are all metal-medium-metal type capacitors; the first inductor, the second inductor, the third inductor and the fourth inductor are annular inductors;

an air bridge structure is arranged at the port of the annular inductor, and the air bridge structure is formed by multiple layers of metals;

the annular inductor comprises annular metal wires and rectangular metal wires, when the annular inductor is manufactured, the intersection of the annular metal wires and the rectangular metal wires is broken to form gaps, a first layer of metal is arranged on the annular metal wires, the rectangular metal wires are unchanged, a second layer of metal is arranged on the annular metal wires, all the annular metal wires are communicated, the rectangular metal wires are unchanged, and the annular inductor with the air bridge structure is manufactured;

the metal-dielectric-metal type capacitor comprises a first polar plate, a dielectric layer and a second polar plate which are arranged in a stacked manner;

when the metal-medium-metal type capacitor is manufactured, a first layer of metal is manufactured, a first rectangular port is manufactured to be connected with the first layer of metal to serve as a second polar plate, a layer of silicon nitride is manufactured in an effective area of the second polar plate to serve as a medium layer, a second layer of metal is manufactured on the silicon nitride, and a second rectangular port is manufactured to be connected with the second layer of metal to serve as the first polar plate, so that the metal-medium-metal type capacitor is manufactured;

the high-isolation low-loss integrated passive miniature duplexer adopts the processing technology of an integrated passive device to design a metal transmission line, a toroidal inductor and a metal-medium-metal capacitor, and is connected in parallel-series by combining an air bridge structure.

2. The high isolation low loss integrated passive micro-duplexer of claim 1, wherein: the low-pass filter further comprises a first grounding block and a second grounding block, wherein the grounding end of the first inductor and the first capacitor after being connected in parallel is connected with the first grounding block, and the grounding end of the second inductor and the third capacitor after being connected in parallel is connected with the second grounding block.

3. The high isolation low loss integrated passive micro-duplexer of claim 1, wherein: the high-pass filter further comprises a third grounding block and a fourth grounding block, wherein the third inductor and the sixth capacitor are connected in series and then connected with the third grounding block, and the fourth inductor and the eighth capacitor are connected in series and then connected with the fourth grounding block.

4. The high isolation low loss integrated passive micro-duplexer of claim 1, wherein: the inductance and capacitance values in the low-pass filter are calculated as follows:

ω _c ＝2mf _c

wherein L represents inductance, C represents capacitance, Ω _C Representing the cut-off frequency, solving the inductance value of the prototype series-parallel inductor by g in the inductance formula, and solving the capacitanceG in the formula represents the capacitance value of the prototype series-parallel capacitor, gamma ₀ Represents the impedance scale factor, omega _C Represents the angular cut-off frequency, Z ₀ Represents port impedance, g ₀ Represents the source conductance, f _C Indicating the operating frequency.

5. The high isolation low loss integrated passive micro-duplexer of claim 1, wherein: the inductance and capacitance values in the high pass filter are calculated as follows:

wherein L represents inductance, C represents capacitance, Ω _C Represents the cut-off frequency, gamma ₀ Represents the impedance scale factor, omega _C And (3) expressing the angular cutoff frequency, solving the inductance value of the prototype parallel-series inductor by g in an inductance formula, and solving the capacitance value of the prototype parallel-series capacitor by g in a capacitance formula.

6. Use of a high isolation low loss integrated passive micro-duplexer according to any of claims 1 to 5 in duplex communication.