CN113206644B - High-efficiency distributed power amplifier with reconfigurable bandwidth - Google Patents

Abstract

The invention discloses a high-efficiency distributed power amplifier with reconfigurable bandwidth, which comprises a plurality of gain modules arranged between an input transmission line and an output transmission line in parallel, wherein the input transmission line and the output transmission line are both connected with a plurality of impedance elements in series; at least one impedance element is set as a reconfigurable impedance element, and a reconfigurable capacitance unit is connected in parallel to at least one capacitor C. The distributed power amplifier can realize the reconstruction of the working frequency bands of the two amplifiers, breaks the limit of bandwidth on efficiency and improves the power additional efficiency of the amplifier.

Description

A high-efficiency distributed power amplifier with reconfigurable bandwidth

technical field

The present invention relates to a communication filter element, in particular to a high-efficiency distributed power amplifier with reconfigurable bandwidth with continuous frequency tunable characteristics.

Background technique

In the past 20 years, in the frequency band of 2-18GHZ, multi-octave broadband power amplifiers have been paid more and more attention. Distributed amplifiers with broadband characteristics are very suitable topology structures. At present, the design of distributed power amplifiers is as follows: There are two ways: (1) The structure of NDPA is adopted. This structure uses the characteristics of the traveling wave structure and current superposition of the distributed amplifier. The power matching of the output terminals of the transistors at all levels can be connected with the characteristic impedance of the artificial drain transmission lines at all levels, so as to The characteristic impedance of the drain transmission lines at all levels can be controlled to achieve power matching at the output of the transistor, thereby completing the design of high output power and high efficiency power amplifiers; (2) Distributed power amplifier structure based on independent bias, this structure The design is based on the analysis of traditional distributed amplifiers. This structure is a uniform structure, and the drains of the transistors at all levels are uniformly biased, because the current increases from the first stage to the last stage, resulting in the transistor from the first stage to the last stage. The output power of the transistor is gradually increased, which means that only the transistor of the last stage can output saturated power, and the DC power consumption of the transistors of the previous stages is the same as that of the last stage, then the output of the transistors of the previous stages The voltage swing is undoubtedly wasted, so an independent bias structure is proposed. As shown in Figure 1, Zd is the characteristic impedance of the drain transmission line, Zg is the characteristic impedance of the gate transmission line, and Rg is the terminal resistance of the gate transmission line. , used to provide a good match, C is the capacitor, which plays the role of isolating the different drain voltages of each transistor, L is the inductance, which forms a high-pass filter together with the capacitor, and then combines with the drain transmission line to form a band-pass structure At the same time, the more important role of L is to feed the drain voltage, and LG is the gate-fed choke coil. The principle of this structure is that the drain bias voltage of the first stage to the last stage transistor increases linearly. (The leftmost transistor is the first stage, and the number of stages to the right increases in turn), so that the output voltage swing of the transistor will not be wasted. The biased distributed power amplifier structure can have an efficiency of 50%, but the actual effect is not very efficient due to many non-ideal factors.

However, the problem of the above two types of amplifiers is limited by the broadband matching itself. According to the Bode-Fano criterion, the matching bandwidth is inversely proportional to the matching effect, that is to say, the wider the bandwidth, the worse the matching effect. For amplifiers, the broadband structure is less efficient than the narrowband structure, and the efficiency is inherently limited by the frequency band.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the above problems and provide a high-efficiency distributed power amplifier with reconfigurable bandwidth.

The purpose of the present invention is to achieve this, to provide a high-efficiency distributed power amplifier with reconfigurable bandwidth, including multiple gain modules arranged in parallel between the input transmission line and the output transmission line, and both the input transmission line and the output transmission line are connected in series with A plurality of impedance elements, each of the gain modules is inserted between two impedance elements, each gain module includes a transistor, the gate of the transistor is connected to the input transmission line through a parallel capacitor C and a resistor R, and the drain of the transistor is connected to the input transmission line. The output transmission line is connected; at least one impedance element is set as a reconfigurable impedance element, and at least one of the capacitors C is connected in parallel with a reconfigurable capacitor unit.

Preferably, a plurality of independent biases are set on the output transmission line, and one bias is shared on the input transmission line, so as to realize independent bias control of the transistors.

Preferably, it includes five gain modules, which are sequentially from the input end to the output end: a first-stage gain module, a second-stage gain module, a third-stage gain module, a fourth-stage gain module and a fifth-stage gain module; The input transmission line and the output transmission line between the first-stage gain module and the third-stage gain module are both set as reconfigurable transmission lines, and the reconfigurable transmission line consists of a primary coil and a secondary coil arranged in the primary coil. It consists of a coil and a control switch added to the secondary coil. The primary coil is connected to the first-stage gain module, the second-stage gain module and the third-stage gain module through port 1, port 2 and port 3 in turn. By switching the secondary coil The state of the control switch in the center enables reconfigurability of the transmission line impedance.

Preferably, the reconfigurable capacitor unit includes capacitors C1 and C2 connected in parallel with each other, and a first switch tube is connected in series with the capacitor C2, and the equivalent capacitance value of the reconfigurable capacitor unit is realized by switching the state of the first switch tube. Refactorable.

Preferably, when the first switch tube is turned on, the first switch tube is equivalent to a resistor; when the first switch tube is turned off, the first switch tube is equivalent to a capacitor, and the capacitance of the capacitor is much smaller than C2.

Preferably, an adjustable resistance unit is connected in parallel with the terminal resistance of the input transmission line. The adjustable resistance unit includes resistors R1 and R2 connected in parallel with each other, and a second switch tube is connected in series with the resistor R2. The equivalent resistance of the adjustable resistance unit can be reconfigured.

Preferably, when the second switch tube is turned on, the second switch tube is equivalent to a resistor; when the second switch tube is turned off, the second switch tube is equivalent to a capacitor, and the equivalent resistance of the adjustable resistance unit is R1.

Preferably, the primary coil and the secondary coil are both transformer coils, the primary coil is a symmetrical structure, and the equivalent length of the coil segment between port 1 and port 2 and the coil segment between port 2 and port 3 are the same .

Preferably, a DC blocking capacitor is respectively connected in series with the output transmission lines between the second-stage gain module and the third-stage gain module and between the third-stage gain module and the fourth-stage gain module.

Preferably, when the control switch and the second switch tube are in the off state and the first switch tube is in the on state, the working frequency band of the amplifier is 2GHZ-10GHZ; when the control switch and the second switch tube are in the on state , and when the first switch tube is in the off state, the working frequency band of the amplifier is 10GHZ-18GHZ.

The remarkable progress of the present invention is mainly reflected in:

The provided high-efficiency distributed power amplifier with reconfigurable bandwidth can realize the reconfiguration of the working frequency bands of 2-10GHZ and 10-18GHZ two amplifiers, break the limitation of bandwidth on efficiency, and convert the bandwidth of 2-18GHZ. The power added efficiency of the power amplifier is increased to more than 25%. In addition, based on the arrangement of the amplifier circuit structure, compared with the existing 2-18GHZ power amplifier chip, the present invention has a smaller area (3.6*1.7mm ² ), which can better meet the requirement of miniaturization.

Description of drawings

Fig. 1 is the circuit schematic diagram of the existing independent bias distributed amplifier;

2 is a schematic circuit diagram of a distributed power amplifier according to an embodiment of the present invention;

3 is a schematic structural diagram of a reconfigurable transmission line according to an embodiment of the present invention;

4 is an equivalent schematic diagram of a reconfigurable capacitor unit according to an embodiment of the present invention;

5 is an equivalent schematic diagram of an adjustable resistance unit according to an embodiment of the present invention;

FIG. 6 is a simulated efficiency curve diagram of a distributed power amplifier according to an embodiment of the present invention;

FIG. 7 is a simulated output power curve diagram of a distributed power amplifier according to an embodiment of the present invention.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings. It should be noted that the embodiments of the present invention are not limited to the provided examples.

Referring to Fig. 2, in the solution of the embodiment of the present invention, a high-efficiency distributed power amplifier with reconfigurable bandwidth includes an input transmission line connected to the signal input end IN, and an output transmission line connected to the signal output end OUT, and a plurality of gain modules arranged in parallel between the input transmission line and the output transmission line, the input transmission line and the output transmission line are both connected with a plurality of impedance elements in series, and each of the gain modules is inserted between the two impedance elements, each Each gain module includes transistors (Q1, Q2, Q3, Q4, Q5), the gate of the transistor is connected to the input transmission line through a capacitor C and a resistor R in parallel with each other, and the drain of the transistor is connected to the output transmission line. The function of DC feeding; at least one impedance element is set as a reconfigurable impedance element, and at least one of the capacitors C is connected in parallel with a reconfigurable capacitor unit. It can be understood that the impedance element includes any one of capacitance, inductance, and resistance elements. As a preferred option, referring to FIG. 2, an inductance element is used in this embodiment, and Zd is a series connection on the output transmission line. The characteristic impedance of the inductive element, Zg is the characteristic impedance of the inductive element in series on the input transmission line. A reconfigurable impedance element can be understood as a characteristic impedance of the impedance element in a circuit that can be switched and changed. Similarly, a reconfigurable capacitive unit can be understood as a capacitive unit whose capacitance value can be changed. In this embodiment, by arranging a reconfigurable impedance element and a reconfigurable capacitor unit in the distributed amplifier circuit, the equivalent inductance values of different Zg and Zd and the switching of different equivalent capacitance values of the reconfigurable capacitor unit are realized, and further The switching of the cut-off frequency of the upstream amplifier is realized, thus the switching of the working frequency band of the amplifier is completed, which is equivalent to realizing the design of multiple amplifiers with different working frequency bands, and the integration degree is improved. Further, based on the amplifier of this embodiment, a wide working frequency band can be divided into a plurality of smaller working frequency bands, so that the working frequency band of the amplifier is reduced, so that the efficiency is improved compared with the wider overall working frequency band. Improvement, that is, breaking the limitation of the frequency band on efficiency by shortening the bandwidth and switching the bandwidth again.

As a preferred implementation, the amplifier of this embodiment includes five gain modules, which are sequentially from the input end to the output end: a first-stage gain module, a second-stage gain module, a third-stage gain module, and a fourth-stage gain module. The first stage gain module and the fifth stage gain module; the input transmission line and the output transmission line between the first stage gain module and the third stage gain module are set as reconfigurable transmission lines, as shown in Figure 2 and Figure 3. The input transmission line and the reconfigurable output transmission line have the same structure, and the reconfigurable transmission line consists of the primary coil, the secondary coil arranged in the primary coil, and the control switches SW (SW1, SW2), the main coil is connected to the first stage gain module, the second stage gain module and the third stage gain module through port 1, port 2 and port 3 in sequence, the coil segment between port 1 and port 2 and port 2 The coil segment between the port 3 and the port 3 is equivalent to the transmission line. The length of the equivalent transmission line between the port 1 and the port 2 and between the port 2 and the port 3 is changed by the on-off of the control switch in the secondary coil, that is, the transmission line is realized. Reconstruction of effective inductance value. It can be understood that between port 1 and port 2 and between port 2 and port 3, the inductance of the primary coil is adjusted through the secondary coil with a control switch. When the control switch is in the off state, the port 1 and the The equivalent resistance between port 2 and between port 2 and port 3 is mainly contributed by the parasitic resistance of the primary coil, and the equivalent inductance is basically equal to the self-inductance of the primary coil, that is, the length of the equivalent transmission line is the primary coil itself; When the control switch is in the on state, the equivalent resistance between port 1 and port 2 and between port 2 and port 3 is contributed by the parasitic resistance of the primary coil, the secondary coil and the parasitic resistance of the control switch, equivalent to The inductance is reduced relative to the self-inductance of the main coil, and the length of the equivalent transmission line at this time is reduced relative to the main coil itself, so that the equivalent inductance value can be switched in different switching states, so that the amplifier can be matched different working frequency bands. Further preferably, the primary coil and the secondary coil are both transformer coils, the primary coil is a symmetrical structure, and the coil segment between port 1 and port 2 is equivalent to the coil segment between port 2 and port 3. same length.

As a preferred implementation, referring to FIG. 4(a), a schematic diagram of the reconfigurable capacitor unit of this embodiment is shown. The reconfigurable capacitor unit includes capacitors C1 and C2 connected in parallel with each other. A first switch tube SW _C is connected in series with C2 , and the reconfiguration of the equivalent capacitance value of the reconfigurable capacitor unit is realized by switching the on-off state of the first switch tube SW _C . Further, (b) in FIG. 4 is an equivalent circuit diagram when the first switch is turned on. When the first switch is turned on, a part of the loss will be introduced, and the first switch is equivalent to the parasitic resistance Ron, At this time, the equivalent capacitance value of the reconfigurable capacitor unit is the sum of the capacitance values of C1 and C2; (c) in FIG. 4 is an equivalent circuit diagram when the first switch is turned off. When the first switch is turned off , the parasitic capacitance Coff is introduced into the first switch tube. Since the first switch tube is connected in series with the capacitor C2 in the form of the parasitic capacitance Coff, and the parasitic capacitance Coff of the first switch tube is configured to be much smaller than C2, the reconfigurable capacitance unit at this time is equal to The effective capacitance is the sum of the parasitic capacitances Coff and C1. Therefore, the switching of the equivalent capacitance value is realized through the reconfigurable capacitor unit to match the different working frequency bands of the amplifier. As a preference, referring to Fig. 2, a reconfigurable capacitor unit is connected in parallel with the capacitors C of the first, third, fourth and fifth gain modules respectively, and each reconfigurable capacitor unit (Csw _1. Csw ₂ , Csw ₃ , Csw ₄ , ) realize the reconfiguration of the capacitance value by switching the on-off state of the first switch.

As a preferred embodiment, an adjustable resistance unit Rsw is connected in parallel with the terminal resistance of the input transmission line. Referring to FIG. 5 (a), the schematic diagram of the adjustable resistance unit of this embodiment is shown. The resistance unit includes resistors R1 and R2 connected in parallel with each other, and a second switch tube SW _R is connected in series with the resistor _R2 . Further, referring to (b) of FIG. 5, the equivalent circuit diagram of the second switch tube is shown in the on state. When the second switch tube is turned on, the parasitic resistance Ron of the switch tube will be introduced, and the parasitic resistance and R2 will be introduced. connected in series, and then in parallel with R1; refer to (c) in Figure 5 for the equivalent circuit diagram when the second switch is turned off. When the second switch is turned off, the parasitic capacitance of the second switch will be introduced. Coff, the gate width of the second switch can be configured to be small enough, so that the parasitic capacitance Coff of the second switch in the off state is also small enough, so that the branch of the second switch is open for the required frequency band. , the equivalent resistance value of the adjustable resistance unit is only R1 at this time, thus realizing two resistance values in the two working frequency bands of the amplifier.

As a preferred embodiment, when the control switch and the second switch tube are in the off state and the first switch tube is in the on state, the working frequency band of the amplifier is 2GHZ-10GHZ; when the control switch and the second switch tube are in the on state When the tube is in an on state and the first switch tube is in an off state, the working frequency band of the amplifier is 10GHZ-18GHZ. It can be understood that, in this embodiment, switching the operating frequency bands of the amplifier 2-10GHZ and 10-18GHZ is to switch the upstream cut-off frequency of the amplifier, and the downstream cut-off frequency does not need to be switched, which is equivalent to designing the 2-10GHZ amplifier and 2. -18GHZ amplifier, and for 2-18GHZ amplifier, only the gain and efficiency of 10-18GHZ can be optimized. According to the principle of distributed amplifiers, the upstream cut-off frequencies are 10GHZ and 18GHZ respectively. Therefore, the equivalent inductance value of Zg and Zd of the amplifier in the 2-10GHZ frequency band and the equivalent capacitance value of the reconfigurable capacitor unit are required to be higher than those in the 10-18GHZ frequency band. big. Based on this, when the first switch is in the on state, the equivalent capacitance of the reconfigurable capacitor unit is reconfigured into a large capacitor, corresponding to the 2-10GHZ frequency band; and when the first switch is in the off state, The equivalent capacitance value of the reconfigurable capacitor unit is reconfigured into a small capacitor, corresponding to the 10-18GHZ frequency band; when the control switch is in the off state, the main coil is between port 1 and port 2 and between port 2 and port 2 The length of the equivalent transmission line between 3 is the primary coil itself, corresponding to the 2-10GHZ frequency band, when the control switch is in the off state, the primary coil is between port 1 and port 2 and between port 2 and port 3 The length of the equivalent transmission line between them is the primary coil itself, which is greater than the length of the equivalent transmission line when the control switch is on The value is greater than the equivalent inductance value when the control switch is in the off state.

As a preferred implementation manner, the output transmission line is provided with a plurality of independent biases, and the input transmission line shares one bias, so as to realize the bias control of the transistor. As a preferred example, as shown in FIG. 2 , bias voltages Vd1 , Vd2 and Vd3 are sequentially loaded with the bias voltages Vd1 , Vd2 and Vd3 on the drains of the transistors of the first-stage gain module, the third-stage gain module and the fifth-stage gain module. The flow coil is powered, and a common bias voltage Vg is loaded at the terminal of the input transmission line. It can be understood that, by switching the bias voltages of the control switch, the first switch tube and the second switch tube in the above embodiment, the on-off state of the control switch, the first switch tube and the second switch tube can be changed. , so that the switching of the working frequency band of the amplifier can be realized more quickly.

As a preferred embodiment, a DC blocking capacitor Cd is connected in series with the output transmission line between the second-stage gain module and the third-stage gain module and between the third-stage gain module and the fourth-stage gain module, respectively. One of the functions of the capacitor Cd is to isolate the different drain voltages of each transistor.

As shown in FIG. 6 , it is the simulation result of the efficiency (PAE) of the high-efficiency distributed power amplifier with reconfigurable bandwidth according to the embodiment of the present invention. Under the input power of 28dBm, it achieves > 25% efficiency with a peak PAE of 37%. As shown in FIG. 7, it is the simulation result of the output power (Pout) of the high-efficiency distributed power amplifier with reconfigurable bandwidth according to the embodiment of the present invention. Under the input power of 28dBm, it has achieved > 33dBm output power, of which the peak output power is 35.8dBm.

It should be noted that the above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Changes or substitutions should be included within the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims (9)

1. a high-efficiency distributed power amplifier with reconfigurable bandwidth, comprising multiple gain modules arranged in parallel between the input transmission line and the output transmission line, the input transmission line and the output transmission line are all connected in series with a plurality of impedance elements, it is characterized in that : each of the gain modules is inserted between two impedance elements, each gain module includes a transistor, the gate of the transistor is connected to the input transmission line through a parallel capacitor C and a resistor R, and the drain of the transistor is connected to the output transmission line; At least one impedance element is set as a reconfigurable impedance element, and at least one of the capacitors C is connected in parallel with a reconfigurable capacitor unit; including five of the gain modules, from the input end to the output end, the order is: first-stage gain module, the second-stage gain module, the third-stage gain module, the fourth-stage gain module and the fifth-stage gain module; the input transmission line and the output transmission line between the first-stage gain module and the third-stage gain module are all set to be configurable. A reconfigured transmission line consisting of a primary coil, a secondary coil arranged in the primary coil, and a control switch added to the secondary coil, the primary coil passing through port 1, port 2 and port 1 3. Connect the first-stage gain module, the second-stage gain module and the third-stage gain module in sequence, and realize the reconfiguration of the transmission line impedance by switching the state of the control switch in the secondary coil. 2. The high-efficiency distributed power amplifier with reconfigurable bandwidth according to claim 1, wherein a plurality of independent biases are set on the output transmission line, and a bias is shared on the input transmission line to achieve Independent bias control of transistors. 3 . The high-efficiency distributed power amplifier with reconfigurable bandwidth according to claim 1 , wherein the reconfigurable capacitor unit comprises capacitors C1 and C2 connected in parallel with each other, and a first switch tube is connected in series with the capacitor C2 . , by switching the state of the first switch tube, the reconfigurability of the equivalent capacitance value of the reconfigurable capacitor unit is realized. 4. The high-efficiency distributed power amplifier with reconfigurable bandwidth according to claim 3, wherein when the first switch is turned on, the first switch is equivalent to a resistance; when the first switch is turned off , the first switch tube is equivalent to a capacitor, and the capacitance of the capacitor is much smaller than C2. 5. The high-efficiency distributed power amplifier with reconfigurable bandwidth according to claim 3, wherein an adjustable resistance unit is connected in parallel on the terminal resistance of the input transmission line, and the adjustable resistance unit includes a parallel resistance R1 and R2, a second switch tube is connected in series with the resistor R2, and the equivalent resistance value of the adjustable resistance unit can be reconfigured by switching the state of the second switch tube. 6. The high-efficiency distributed power amplifier with reconfigurable bandwidth according to claim 5, wherein when the second switch is turned on, the second switch is equivalent to a resistance; when the second switch is turned off , the second switch tube is equivalent to a capacitor, and the equivalent resistance value of the adjustable resistance unit is R1. 7. The high-efficiency distributed power amplifier with reconfigurable bandwidth according to claim 1, wherein the primary coil and the secondary coil are both transformer coils, the primary coil is a symmetrical structure, and the port 1 and the port The equivalent length of the coil segment between port 2 and port 3 is the same. 8. The high-efficiency distributed power amplifier with reconfigurable bandwidth according to claim 1, characterized in that, between the second-stage gain module and the third-stage gain module and between the third-stage gain module and the fourth-stage gain module A DC blocking capacitor is respectively connected in series on the output transmission line between them. 9 . The high-efficiency distributed power amplifier with reconfigurable bandwidth according to claim 5 , wherein when the control switch and the second switch transistor are in an off state, and the first switch transistor is in an on state. 10 . , the working frequency band of the amplifier is 2GHZ-10GHZ; when the control switch and the second switch tube are in the on state, and the first switch tube is in the off state, the working frequency band of the amplifier is 10GHZ-18GHZ.

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