CN108808186A - A kind of four work device of reconfigurable microwave - Google Patents

Abstract

The invention discloses a reconfigurable microwave quadruplexer. Each channel of the quadruplexer adopts a second-order folded loaded capacitive resonator, and each channel is coupled together through a distributed coupling technology, without matching circuits and can maintain a good matching features and adjustable features. Electric coupling and magnetic coupling exist between the second-order resonators of the present invention, which is beneficial to generate transmission zero point outside the band and improve the selectivity of the stop band. Secondly, this folded resonator has a very weak loading effect on the input feeder, improves the isolation between output ports, and has good matching. Utilizing the wide stop band of the slow wave resonator and the characteristics of effectively suppressing high-order modes, the lowest pass band uses a slow wave folded resonator to reduce the impact on other channel characteristics, especially the highest frequency, and is also conducive to further reducing reconfigurable Quadruplexer size.

Description

A reconfigurable microwave quadruplexer

technical field

The invention relates to the technical field of microwave devices, in particular to a reconfigurable microwave quadruplexer.

Background technique

Multiplexer A device that can divide a broadband signal into several frequency channel signals plays an important role in mobile communication systems. Previous multiplexers basically used a cavity structure with high Q value and low loss, but generally occupied a large volume and were inconvenient to be used in reconfigurable systems. With the rapid development of today's communication systems, people's research on reconfigurable multiplexers is gradually rising, but currently there are only a small number of reconfigurable duplexers based on microstrip structures, which can only be adjusted for simple two channels. It cannot be applied in a wider range of communication scenarios, and there is very little research on multi-channel reconfigurable multiplexers.

Contents of the invention

In view of the shortcomings and deficiencies of the prior art described above, the object of the present invention is to provide a four-channel reconfigurable multiplexer, each channel adopts a second-order folding-shaped loaded capacitive resonator, and each channel is coupled in a distributed coupling technology. Together, no matching circuit is required and good matching and adjustable characteristics can be maintained. The reconfigurable quadruplexer proposed by the present invention solves the loading effect of multi-channels in a simple and efficient way and maintains good matching characteristics, and plays a guiding role in the research of other reconfigurable multiplexers.

The present invention realizes through following technical scheme:

A reconfigurable microwave quadruplexer, including an input feeder port, a first output feeder port, a second output feeder port, a third output feeder port, a fourth output feeder port, a first adjustable filter, a second An adjustable filter, a third adjustable filter and a fourth adjustable filter; the first frequency channel is formed by the first input feeder port, the first adjustable filter and the first output feeder port, and the first frequency channel is formed by the first The two input feeder ports, the second adjustable filter and the second output feeder port form a second frequency channel, and the third input feeder port, the third adjustable filter and the third output feeder port form a third frequency channel, A fourth frequency channel is formed by the fourth input feeder port, the fourth adjustable filter and the fourth output feeder port; wherein, the four adjustable filters are all second-order folding type loaded variable capacitance resonators, and the two The first-order resonators are coupled in a symmetrical structure; the first tunable filter uses a ladder-type impedance resonator, and the second-fourth tunable filter uses a uniform-type impedance resonator.

The present invention adopts the second-order folding type loaded variable capacitance resonator, couples each channel together through distributed coupling technology, does not need to design any matching circuit, effectively realizes the impedance matching between the total port and each channel, and the input port and each channel The coupling coefficient of the channel only needs to adjust the coupling distance appropriately, and further reduces the size of the quadruplexer; the first channel uses a ladder-type impedance resonator, which can effectively suppress its high-order resonance mode, thereby widening the stop band.

As a preferred mode, the input feeder port is a long microstrip line, and the first-fourth adjustable filter is connected to the input feeder port through gap capacitive coupling, the first adjustable filter and the second adjustable The filters are located on the same side in the length direction of the microstrip line, and the third tunable filter and the fourth tunable filter are located on the other side in the length direction of the microstrip line. On the one hand, the above-mentioned design can achieve the required external quality factor by simply adjusting the coupling distance with the input feeder port; on the other hand, it does not require any matching circuit, which further reduces the design complexity and reduces the occupied size at the same time.

As a preferred method, each channel is a second-order resonator, and the synchronization is adjustable, so the coupling coefficient and external quality factor of each channel are determined by the following formula:

In the formula, M ₁₂ is the coupling coefficient between second-order resonators, FBW is the relative width of the filter, Q _e1 and Q _e2 are the external quality factors of the input and output ports of the filter, and g ₀ , g ₁ , g ₂ are all Select the low-pass prototype component value corresponding to the filter type. According to the given filter performance index, the coupling coefficient between resonators and the external quality factor of the input and output ports are obtained through preliminary synthesis, and then the required parameter values are achieved by adjusting the coupling spacing between resonators and the distance to the input and output ports.

As a preferred mode, the first tunable filter adopts a slow-wave structure resonator formed by symmetrical coupling of second-order ladder impedance resonators, and the second-fourth tunable filter is formed by symmetrical coupling of second-order uniform impedance resonators half-wavelength structural resonators. A slow-wave structure resonator is used to widen the stop band and reduce the adverse effects of its high-order resonance mode on other channels.

As a preferred mode, in the first-fourth channels, the second-order resonators are folded into two symmetrically arranged U-shaped structures, one end of the first U-shaped structure is grounded through a variable capacitor, and the variable capacitor is located One end is coupled to the corresponding output feeder port, the other end of the first U-shaped structure is coupled to one end of the second U-shaped structure, the other end of the second U-shaped structure is grounded through a variable capacitor, and is coupled to the input feeder port. The above design makes the second-order resonators coupled in a symmetrical structure, the middle is electrical coupling, and the ground part of the two resonators loaded with variable capacitance is magnetic coupling. The required coupling coefficient can be achieved by selecting an appropriate coupling distance, and there is an out-of-band Transmission zeros improve selectivity.

As a preferred manner, the coupled ends of the first U-shaped structure and the second U-shaped structure are grounded through inductance and capacitance.

As a preferred manner, the variable capacitance adopts a varactor diode. A wide frequency adjustable range can be achieved by selecting a varactor diode with a large variable capacitance ratio, and a high-frequency substrate material with a small loss should also be selected.

The present invention has following advantage and beneficial effect:

The present invention adopts the distributed coupling technology to connect the four-way adjustable filter with the input feeder port in the form of weak gap coupling. With this method, no matching circuit needs to be designed, so that the design is fast and the size of the quadruplexer is reduced. . Each channel is a second-order folded type loaded variable capacitance resonator. There is electrical coupling and magnetic coupling between such second-order resonators, which is conducive to generating transmission zeros outside the band and improving the selectivity of the stop band. The reconfigurable characteristic of the quadruplexer is realized by changing the capacitance value of the variable capacitor loaded on the resonator of each channel. Secondly, this folded resonator has a very weak loading effect on the input feeder, improves the isolation between output ports, has good matching, and has high practical application value. Utilizing the wide stop band of the slow wave resonator and the characteristics of effectively suppressing high-order modes, the lowest pass band uses a slow wave folded resonator to reduce the impact on other channel characteristics, especially the highest frequency, and is also conducive to further reducing reconfigurable Quadruplexer size. A wide reconfigurable range per channel is achieved by selecting a varactor diode with a large varactor ratio.

Description of drawings

The drawings described here are used to provide a further understanding of the embodiments of the present invention, constitute a part of the application, and do not limit the embodiments of the present invention. In the attached picture:

FIG. 1 is a schematic plan view of a reconfigurable microwave quadruplexer according to the present invention.

Fig. 2 is a schematic diagram of the structure of the reconfigurable microwave quadruplexer of the present invention.

Fig. 3 is the initial result of the reconfigurable microwave quadruplexer of the present invention.

FIG. 4 shows the return loss and insertion loss in the process of only adjusting the first channel of the quadruplexer of the present invention.

FIG. 5 shows the isolation during the process of only adjusting the first channel of the quadruplexer of the present invention.

FIG. 6 shows the return loss and insertion loss in the process of only adjusting the second channel of the quadruplexer of the present invention.

FIG. 7 shows the isolation in the process of only adjusting the second channel of the quadruplexer of the present invention.

FIG. 8 shows the return loss and insertion loss in the process of only adjusting the third channel of the quadruplexer of the present invention.

FIG. 9 shows the isolation in the process of only adjusting the third channel of the quadruplexer of the present invention.

FIG. 10 shows the return loss and insertion loss in the process of only adjusting the fourth channel of the quadruplexer of the present invention.

FIG. 11 shows the isolation in the process of only adjusting the fourth channel of the quadruplexer of the present invention.

FIG. 12 shows the return loss and insertion loss in Case 1 where all four channels of the quadruplexer of the present invention are adjusted.

FIG. 13 shows the return loss and insertion loss in Case 2 where all four channels of the quadruplexer of the present invention are adjusted.

Marks and corresponding device names in the drawings:

1-input feeder port, 2-first output feeder port, 3-second output feeder port, 4-third output feeder port, 5-fourth output feeder port, 6-first frequency channel, 7-second frequency Channel, 8-third frequency channel, 9-fourth frequency channel, 10-variable capacitor, 11-inductor, 12-capacitor, 13-ground terminal, 14-air cavity, 15-metal formation.

Detailed ways

In order to make the purpose, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the examples and accompanying drawings. As a limitation of the present invention.

Example

The reconfigurable microwave quadruplexer implemented in this implementation uses distributed coupling technology to connect the four adjustable filters to the input feeder port in the form of weak gap coupling. With this method, no matching circuit needs to be designed, so that Fast design and reduced quadruplexer size. Each channel is a second-order folded type loaded variable capacitance resonator. There is electrical coupling and magnetic coupling between such second-order resonators, which is conducive to generating transmission zeros outside the band and improving the selectivity of the stop band. Secondly, this folded resonator has a very weak loading effect on the input feeder, improves the isolation between output ports, has good matching, and has high practical application value. Utilizing the wide stop band of the slow wave resonator and the characteristics of effectively suppressing high-order modes, the lowest pass band uses a slow wave folded resonator to reduce the impact on other channel characteristics, especially the highest frequency, and is also conducive to further reducing reconfigurable Quadruplexer size. A wide reconfigurable range per channel is achieved by selecting a varactor diode with a large varactor ratio.

As shown in Figure 1-2, the quadruplexer of this embodiment includes an input feeder port 1, a first output feeder port 2, a second output feeder port 3, a third output feeder port 4, and a fourth output feeder port 5 , the first adjustable filter, the second adjustable filter, the third adjustable filter and the fourth adjustable filter; by the first input feeder port, the first adjustable filter and the first output feeder port A first frequency channel 6 is formed, a second frequency channel 7 is formed by the second input feeder port, a second adjustable filter and a second output feeder port, and a second frequency channel 7 is formed by the third input feeder port, the third adjustable filter And the 3rd output feeder port constitutes the 3rd frequency channel 8, constitutes the 4th frequency channel 9 by described 4th input feeder port, the 4th adjustable filter and the 4th output feeder port; Wherein, four adjustable filters all It is a second-order folding type loaded variable capacitance resonator, and the second-order resonators are coupled in a symmetrical structure; the first tunable filter adopts a ladder-type impedance resonator, and the second tunable filter, the third The tunable filter and the fourth tunable filter use uniform impedance resonators.

The first tunable filter uses a slow-wave structure resonator formed by symmetrical coupling of second-order ladder impedance resonators, the first tunable filter uses a ladder-type impedance resonator, the second tunable filter, the second The three tunable filters and the fourth tunable filter adopt half-wavelength structural resonators formed by symmetrical coupling of second-order uniform impedance resonators.

In the first frequency channel, the second frequency channel, the third frequency channel and the fourth frequency channel, the second-order resonators are folded into two symmetrically arranged U-shaped structures, and one end of the first U-shaped structure is variable The capacitor 10 is grounded, and the end where the variable capacitor is located is coupled and connected to the output feeder port of the corresponding channel, the other end of the first U-shaped structure is coupled and connected to one end of the second U-shaped structure, and the other end of the second U-shaped structure is connected through the variable capacitor Grounded and coupled to the input feeder port. The coupled ends of the first U-shaped structure and the second U-shaped structure are grounded through the inductor 11 and the capacitor 12 .

The slow-wave structure adopts a ladder-type impedance resonator, which can effectively suppress its high-order resonance mode. And this kind of resonator has the characteristics of wide stop band and easy to form ultra-narrow band filter.

In the distributed coupling technology, the input port is a relatively long section of microstrip line, and after each adjustable filter is designed, it is indirectly connected to the input port in the form of gap capacitive coupling. On the one hand, the required external quality factor can be achieved simply by adjusting the coupling distance with the input port. On the other hand, no matching circuit is required, further reducing design complexity and reducing footprint.

The folding-shaped loaded capacitive resonator makes the second-order resonators coupled with each other in a symmetrical structure, the middle part is electric coupling, and the part of the two resonators loaded with variable capacitive grounding is magnetic coupling. Selecting the appropriate coupling distance can achieve the required coupling coefficient, and there are transmission zeros outside the band to improve the selectivity.

The channel one, that is, the lowest frequency passband adopts a second-order slow-wave structure resonator, so as to widen the stopband and reduce the adverse effects of its high-order mode on other passbands. In order to reduce the design complexity, the rest of the channels are all half-wavelength loaded variable capacitance resonators, and the initial design center frequency interval between the channels is 400MHz. Choose a varactor diode with a larger variable capacitance ratio to achieve a wide frequency adjustable range, and also choose a high-frequency substrate material with less loss.

The working principle of the present invention is as follows: the design of a multiplexer always needs to be integrated into the design of each channel filter, and the same is true for reconfigurable multiplexers. First of all, by designing a suitable reconfigurable filter, a single filter can have a wide adjustable range and a constant percentage bandwidth, so that the multiplexer may have good characteristics. Secondly, for the design of the filter, the key point is the selection of the resonator structure, and different forms play a decisive factor in the characteristics of the filter. Generally speaking, resonators with a microstrip structure are mostly in the form of an electrical length of half a wavelength, and can be roughly divided into uniform impedance resonators (UIR) and stepped impedance resonators (SIR). One channel of the present invention adopts the slow wave resonator formed by SIR, and the other channels all adopt the form of UIR. After the form of the resonator is determined, it is necessary to design a filter for each channel according to the coupled resonant circuit theory, including two main parameters: coupling coefficient and external quality factor.

The normalized impedance matrix is mainly composed of three parts: coupling coefficient m _ij , external quality factor q _ei , and frequency transformation formula p. So the impedance matrix can be decomposed as:

[Z]=[q]+p[U]-j[m]

Among them, [U] is an n×n unit matrix; [q] is also an n×n matrix, and except q ₁₁ =1/q _e1 and q _nn =1/q _en , other values are 0; [m] is Commonly referred to as the coupling matrix, and is a reciprocal network, so it can be expressed as:

The coupling matrices listed above belong to the case of synchronous tuning, that is, each resonator has the same resonant frequency. Each channel of the reconfigurable quadruplexer of the present invention is a second-order resonator, which is also synchronously adjustable, so the coupling coefficient and external quality factor of each channel can be determined by formulas (1) and (2):

In the formula, M ₁₂ is the coupling coefficient between second-order resonators, FBW is the relative width of the filter, Q _e1 and Q _e2 are the external quality factors of the input and output ports of the filter, and g ₀ , g ₁ , g ₂ are all Select the low-pass prototype component value corresponding to the filter type.

Formulas (1) and (2) can be used for a given filter index for preliminary synthesis to obtain the coupling coefficient and external quality factor between resonators, and then by adjusting the coupling spacing between resonators and the distance to the input and output ports, to achieve The desired parameter value.

After obtaining the coupling coefficient and external quality factor from the resonant circuit theory, it is necessary to determine the physical structure and size of the resonator according to the actual design requirements. The four passband center frequencies of the initial design of the reconfigurable quadruplexer of the present invention are set at: 1.1GHz, 1.5GHz, 1.9GHz and 2.3GHz, with an interval of 400MHz. In order to ensure a high degree of isolation between channels, it is an inevitable requirement of the present invention to introduce a transmission zero point. In general, a filter with n-order resonators can generate n-1 transmission zeros at most, but this design adopts a hybrid electromagnetic coupling method, that is, there are both electrical coupling and magnetic coupling between the second-order resonators, and reasonable control Two coupling sizes allow for a pair of transmission zeros out-of-band to improve frequency selectivity. The resonator is determined to be a folded U-shaped structure, which can achieve the above requirements while reducing the size of the quadruplexer.

When the adjustable filter per channel is designed, the key design point of the multiplexer is the way to combine the four channels. In order to ensure that the quadruplexer can have a wide frequency reconfigurable range, the distributed coupling technology is adopted, that is, the four-way adjustable filter is connected to the input feeder port in the form of capacitive coupling. This effectively realizes the impedance matching between the total port and each channel, and the coupling coefficient between the input port and each channel only needs to properly adjust the coupling distance, while further reducing the size of the quadruplexer.

As shown in Figure 3-13, the simulation results obtained by simulating the reconfigurable microwave quadruplexer in this embodiment show that: in the reconfigurable microwave quadruplexer in this embodiment, the center frequency of each channel can be simultaneously or individually Adjustment, the initial design center frequency is at: 1.1GHz, 1.5GHz, 1.9GHz and 2.3GHz, and the adjustable frequency range of each passband is >350MHz; as can be seen from Figure 3, in the quadruplexer of this embodiment, each channel has a transmission Zero point, the first frequency channel has a wider stop band; and Figure 4-11 shows the return loss, insertion loss and isolation obtained by separately adjusting the first channel, the second channel, the third channel and the fourth channel simulation, When one channel is adjusted individually, it hardly affects the characteristics of other channels; Figure 12-13 shows the return loss, insertion loss and isolation of each channel in the two cases of simultaneous adjustment of all channels, in the whole adjustment During the process, good port matching is maintained and S11<-14dB; it can be seen that the reconfigurable microwave quadruplexer of this embodiment has little influence on each channel when adjusted individually or simultaneously; and the insertion of the four channels Loss can be kept less than 1.8dB throughout the adjustment process, and the isolation between output ports is greater than 30dB.

The specific embodiments described above have further described the purpose, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above descriptions are only specific embodiments of the present invention and are not intended to limit the scope of the present invention. Protection scope, within the spirit and principles of the present invention, any modification, equivalent replacement, improvement, etc., shall be included in the protection scope of the present invention.

Claims (7)

1. a kind of four work device of reconfigurable microwave, which is characterized in that including 1 incoming feeder port, the first output feeder port, Two output feeder ports, third output feeder port, the 4th output feeder port, the first tunable filter, the second adjustable filtering Device, third tunable filter and the 4th tunable filter；By first incoming feeder port, the first tunable filter and first Output feeder port constitutes first frequency channel, by second incoming feeder port, the second tunable filter and the second output Feeder line port constitutes second frequency channel, by third incoming feeder port, third tunable filter and third output feeder Port constitutes third frequency channel, by the 4th incoming feeder port, the 4th tunable filter and the 4th output feeder port Constitute the 4th frequency channel；Wherein, four tunable filters are second order folded form load variable capacitance resonator, and second order is humorous The device that shakes is coupled with symmetrical structure；For first tunable filter using stepped electric impedance resonator, described second-four is adjustable Filter uses uniform type electric impedance resonator.

2. four work device of a kind of reconfigurable microwave according to claim 1, which is characterized in that the incoming feeder port is one Long microstrip line, the described first-the four tunable filter are connected by the capacity coupled mode in gap with incoming feeder port, and first Tunable filter and the second tunable filter are located at the same side of microstrip line length direction, third tunable filter and the 4th adjustable Filter is located at the other side of microstrip line length direction.

3. four work device of a kind of reconfigurable microwave according to claim 1, which is characterized in that every channel is second order resonance Device, synchronizes adjustable, then is determined by following formula with external sort factor per the coefficient of coup in channel：

In formula, M₁₂For the coefficient of coup between second order resonator, FBW is the relative width of filter, Q_e1And Q_e2Respectively filter The external sort factor of input/output port, g₀、g₁、g₂For the corresponding low-pass prototype component value of selected filter type.

4. according to a kind of four work device of reconfigurable microwave of claim 1-3 any one of them, which is characterized in that described first is adjustable Filter uses the slow-wave structure resonator that second order step electric impedance resonator symmetrical coupled is formed, the described second-four adjustable filtering Device uses the half-wavelength structure resonator that second order uniformity electric impedance resonator symmetrical coupled is formed.

5. four work device of a kind of reconfigurable microwave according to claim 4, which is characterized in that in the first-fourth lane, By being folded into two symmetrically arranged U-shaped structures, the first U-shaped structure one end is connect second order resonator by variable capacitance Ground, and end where the variable capacitance is of coupled connections with corresponding output feeder port, the first U-shaped structure other end and second U-shaped Structure one end is of coupled connections, and the other end of the second U-shaped structure is grounded by variable capacitance, and couples company with incoming feeder port It connects.

6. four work device of a kind of reconfigurable microwave according to claim 5, which is characterized in that first U-shaped structure and The end that two U-shaped structures are coupled is by inductance and capacity earth.

7. four work device of a kind of reconfigurable microwave according to claim 5, which is characterized in that the variable capacitance uses transfiguration Diode.