A power amplifier with reconfigurable center frequency and bandwidth

Abstract

The application relates to the technical field of radio frequency wireless communication, in particular to a center frequency and bandwidth reconfigurable power amplifier, which comprises an input port, an input matching network, a stabilizing network, a transistor, a dynamic impedance matching network, a varactor diode DC bias, a reconfigurable band-pass filter network and an output port. The output matching network is designed, the varactor diode junction capacitance adjustable characteristic is utilized to realize the continuous adjustment of the center frequency and bandwidth of the reconfigurable band-pass filter network passband and the dynamic impedance matching between the reconfigurable band-pass filter network and the transistor drain, so that the continuous reconfiguration of the center frequency and bandwidth of the power amplifier is realized, the demand of the multi-frequency band operation of a communication system is met, the frequency adjustable flexibility is improved, the continuous adjustable frequency band range is increased, the frequency selectivity and the power amplifier efficiency are improved, the system complexity is reduced, and the reconfiguration cost is reduced.

Description

Technical Field

[0001] This invention relates to the field of radio frequency wireless communication technology, and in particular to a power amplifier whose center frequency and bandwidth can be reconfigured. Background Technology

[0002] With the rapid growth of wireless communication terminal users and the increasing demands for wireless communication, 4G communication technology can no longer meet the higher requirements in some aspects. Although the application of 5G communication systems is in full swing, in today's era of pursuing the Internet of Everything and increasingly scarce spectrum resources, the interconnection of multiple application terminals will inevitably lead to coverage issues across multiple frequency bands. This necessitates application terminals and base stations to provide multi-mode, multi-band operating standards to solve this problem. Traditional RF systems often achieve multi-band operating standards by using multiple RF receiving links and switching operating bands using switches. The disadvantage of this approach is that it significantly increases the size, cost, and structural complexity of the RF system. As a crucial component in the front-end of the RF system, the power amplifier's performance directly impacts the final performance of the RF system.

[0003] Reconfigurable technology is one of the key technologies for achieving multi-mode / multi-frequency operation standards. Traditional reconfigurable power amplifiers mainly use reconfigurable devices with switching properties such as PIN diodes and RFMEMS to achieve discrete frequency reconfiguration. These discretely reconfigurable power amplifiers generally lack the flexibility of frequency band adjustment, while existing continuously reconfigurable power amplifiers based on varactor diodes and variable capacitors have the problems of narrow adjustable frequency range and poor frequency selectivity of reconfigurable frequency bands. Summary of the Invention

[0004] The purpose of this invention is to provide a power amplifier with reconfigurable center frequency and bandwidth, which aims to solve the problems of narrow adjustable frequency range and poor frequency selectivity of existing reconfigurable power amplifiers.

[0005] To achieve the above objectives, the present invention provides a power amplifier with reconfigurable center frequency and bandwidth, comprising an input port, an input matching network, a stabilizing network, a transistor, a dynamic impedance matching network, a varactor diode DC bias, a reconfigurable bandpass filter network, and an output port. The input port, the input matching network, the stabilizing network, the transistor, the dynamic impedance matching network, the reconfigurable bandpass filter network, and the output port are connected sequentially. The varactor diode DC bias is connected to both the dynamic impedance matching network and the reconfigurable bandpass filter network.

[0006] The reconfigurable bandpass filter network is composed of a cascaded quasi-elliptic low-pass filter network with a ring symmetry structure and a generalized Chebyshev high-pass filter network. The reconfigurable bandpass filter network can achieve continuous adjustment of the passband center frequency and bandwidth.

[0007] The quasi-elliptic low-pass filter network with ring symmetry structure includes two parallel branches that are symmetrically connected vertically. The two parallel branches are connected in a ring by four arc-shaped microstrip lines Curve3, Curve4, Curve5, and Curve6 and two T-shaped microstrip lines Tee2 and Tee5. Each branch includes series microstrip lines TL15, TL16, TL17, TL18, TL19, TL20, and TL21, T-shaped microstrip lines Tee3 and Tee4, DC blocking capacitors C3, C4, and C5, and varactor diodes Cc, Cd, and Ce.

[0008] In the reconfigurable bandpass filter network, microstrip lines TL15, TL16, TL17, TL18, TL19, TL20, TL21, TL22, TL23, TL24, and TL26 are all converted from inductors. Microstrip lines TL18, TL19, TL20, and TL21, together with varactor transistors Cc, Cd, and Ce, form a resonator structure unit. Microstrip lines TL23 and TL24, together with varactor transistor Ch, form a series resonant unit SR3.

[0009] The dynamic impedance matching network includes a π-type matching network and a drain bias network; the π-type matching network includes series microstrip lines TL8, TL9, TL10, TL11, parallel short-circuit microstrip line TL12, cross microstrip line Cross2, T-shaped microstrip line Tee1, DC blocking capacitor C2, and varactors Ca and Cb.

[0010] The adjustable frequency range of the power amplifier's operating frequency band, where both center frequency and bandwidth are reconfigurable, is 0.95–1.9 GHz, with a single reconfigurable frequency band bandwidth of 400 MHz; the adjustable bandwidth range is 1.1–1.8 GHz, with a center frequency of 1.45 GHz.

[0011] This invention discloses a power amplifier with reconfigurable center frequency and bandwidth. The input port receives an RF input signal, and the output port outputs an RF output signal. The input port is adapted to and connected to the input terminal of an input matching network, and the output port is adapted to and connected to the output terminal of a reconfigurable bandpass filter network. The input matching network includes a T-type matching network and a gate bias network. The T-type matching network enables impedance matching between the transistor gate and the input port. The stabilization network consists of a capacitor-resistor parallel network and two series microstrip lines, which are connected in series with the capacitor-resistor parallel network and the transistor gate, respectively. The dynamic impedance matching network includes a π-type matching network and a drain bias network, enabling dynamic impedance matching between the reconfigurable bandpass filter network and the transistor drain. Impedance matching is achieved by cascading a quasi-elliptic low-pass filter network with a ring-symmetric structure and a generalized Chebyshev high-pass filter network. The reconfigurable bandpass filter network enables continuous adjustment of the passband center frequency and bandwidth. By designing the output matching network and utilizing the DC bias of the varactor diode, continuous adjustment of the passband center frequency and bandwidth of the reconfigurable bandpass filter network is achieved, along with dynamic impedance matching between the reconfigurable bandpass filter network and the transistor drain. This enables continuous reconfiguration of the power amplifier's center frequency and bandwidth, meeting the multi-band operation requirements of communication systems, improving frequency adjustability flexibility, increasing the continuously adjustable frequency band range, improving frequency selectivity and power amplifier efficiency, reducing system complexity, lowering reconfiguration costs, and solving the problem of poor frequency selectivity in existing reconfigurable power amplifiers. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a block diagram of a power amplifier with reconfigurable center frequency and bandwidth provided by the present invention.

[0014] Figure 2 This is the overall circuit diagram of a power amplifier with reconfigurable center frequency and bandwidth provided by the present invention.

[0015] Figure 3 This is the circuit diagram of the input matching network of the present invention.

[0016] Figure 4 This is a circuit diagram of the reconfigurable bandpass filter network of the present invention.

[0017] Figure 5 This is the circuit diagram of the dynamic impedance matching network of the present invention.

[0018] Figure 6 The figure shows the simulation results of the S-parameters of the reconfigurable bandpass filter network of this invention, where the center frequency is continuously adjustable.

[0019] Figure 7 This is a simulation result diagram of the S-parameters of the reconfigurable bandpass filter network of the present invention, which has continuously adjustable bandwidth.

[0020] Figure 8 The figure shows the simulation results of the power amplifier efficiency in each frequency band under the continuously reconfigurable center frequency state of this invention.

[0021] Figure 9 This is a simulation result diagram of the power amplifier gain in each frequency band under the continuously reconfigurable center frequency state of the present invention.

[0022] Figure 10 The figure shows the simulation results of the power amplifier efficiency in each frequency band under the continuously reconfigurable bandwidth state of this invention.

[0023] Figure 11 This is a simulation result diagram of the power amplifier gain in each frequency band under the continuously reconfigurable bandwidth state of the present invention.

[0024] In the diagram: 1-Input matching network, 2-Stabilizing network, 3-Transistor, 4-Dynamic impedance matching network, 5-Reconfigurable bandpass filter network, 6-T-type matching network, 7-Gate bias network, 8-Quasi-elliptic low-pass filter network with ring symmetry structure, 9-Generalized Chebyshev high-pass filter network, 10-π-type matching network, 11-Drain bias network, 12-Varactor diode DC bias, 13-Input port, 14-Output port, 15-Output matching network. Detailed Implementation

[0025] Embodiments of the present invention are described in detail below, examples of which are illustrated in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention.

[0026] Please see Figures 1 to 11This invention provides a power amplifier with reconfigurable center frequency and bandwidth, including an input port 13, an input matching network 1, a stabilizing network 2, a transistor 3, a dynamic impedance matching network 4, a varactor diode DC bias 12, a reconfigurable bandpass filter network 5, and an output port 14. The input port 13, the input matching network 1, the stabilizing network 2, the transistor 3, the dynamic impedance matching network 4, the reconfigurable bandpass filter network 5, and the output port 14 are connected in sequence. The varactor diode DC bias 12 is connected to the dynamic impedance matching network 4 and the reconfigurable bandpass filter network 5, respectively.

[0027] In this embodiment, the dynamic impedance matching network 4 and the reconfigurable bandpass filter network 5 constitute the output matching network 1. The input port 13 receives the RF input signal, and the output port 14 outputs the RF output signal. The input port 13 is adapted to and connected to the input terminal of the input matching network 1, and the output port 14 is adapted to and connected to the output terminal of the reconfigurable bandpass filter network 5. The input matching network 1 includes a T-type matching network 6 and a gate bias network 7. The T-type matching network 6 can realize impedance matching between the gate of the transistor 3 and the input port 13. The stabilizing network 2 is composed of a capacitor-resistor parallel network and two series microstrip lines. The two series microstrip lines are connected in series with the capacitor-resistor parallel network and the gate of the transistor 3, respectively. The dynamic impedance matching network 4 includes a π-type matching network 10 and a drain bias network 11. The dynamic impedance matching network 4 can realize impedance matching between the reconfigurable bandpass filter network 5 and the input port 1. The dynamic impedance matching between the drains of transistor 3 is achieved. The reconfigurable bandpass filter network 5 is composed of a cascaded quasi-elliptic low-pass filter network 8 with a ring-symmetric structure and a generalized Chebyshev high-pass filter network 9. The reconfigurable bandpass filter network 5 can achieve continuous adjustment of the passband center frequency and bandwidth. By designing the output matching network, the junction capacitance of the varactor diode is adjusted using the DC bias 12 of the varactor diode, thereby achieving continuous adjustment of the passband center frequency and bandwidth of the reconfigurable bandpass filter network 5 and dynamic impedance matching between the reconfigurable bandpass filter network 5 and the drain of transistor 3. This enables continuous reconfiguration of the center frequency and bandwidth of the power amplifier, meeting the multi-band operation requirements of communication systems, improving frequency adjustment flexibility, increasing the continuously adjustable frequency band range, improving frequency selectivity and power amplifier efficiency, reducing system complexity, reducing reconfiguration costs, and solving the problems of narrow adjustable frequency range and poor frequency selectivity of existing reconfigurable power amplifiers.

[0028] The π-type matching network 10 includes series microstrip lines TL8, TL9, TL10, and TL11, a parallel short-circuited microstrip line TL12, a cross-shaped microstrip line Cross2, a T-shaped microstrip line Tee1, a DC blocking capacitor C2, and varactors Ca and Cb. The left end of TL8 is connected to the drain of transistor 3, and the right end is connected to the left port of Cross2. The anode and cathode of varactor Ca are connected to ground and the lower port of Cross2, respectively. TL9, the DC blocking capacitor C2, TL10, and the varactor Cb are connected in series. The left end of TL9 is connected to the drain of Cross2. The right port of s2 is connected, the anode of the varactor Cb is connected to the left port of Tee1, the lower port of Tee1 is connected to the short-circuited microstrip line TL12, and the two ends of TL11 are respectively connected to the right port of Tee1 and the reconfigurable bandpass filter network 5; the drain bias network 11 includes a microstrip line TL13, an arc-shaped microstrip line Curve2, a microstrip line TL14 connected in series and three filter capacitors connected in parallel to ground, wherein the lower end of TL13 is connected to the upper port of Cross2, and the three filter capacitors connected to ground are respectively connected to the drain DC bias terminal Vds and TL14.

[0029] Furthermore, the reconfigurable bandpass filter network 5 is composed of a cascaded quasi-elliptic low-pass filter network 8 with a ring-symmetric structure and a generalized Chebyshev high-pass filter network 9. The reconfigurable bandpass filter network 5 can achieve continuous adjustment of the passband center frequency and bandwidth.

[0030] In this embodiment, the quasi-elliptic low-pass filter network 8 with a ring-shaped symmetrical structure includes two parallel branches that are symmetrically connected vertically. The two parallel branches are connected in a ring by four arc-shaped microstrip lines Curve3, Curve4, Curve5, and Curve6 and two T-shaped microstrip lines Tee2 and Tee5. Each branch includes series microstrip lines TL15, TL16, TL17, TL18, TL19, TL20, and TL21, T-shaped microstrip lines Tee3 and Tee4, DC blocking capacitors C3, C4, and C5, and varactor diodes Cc, Cd, and Ce. The generalized Chebyshev high-pass filter network includes series microstrip lines TL23, TL24, and TL25, T-shaped microstrip lines Tee6, Tee7, and Tee8, parallel short-circuited microstrip lines TL22 and TL26, DC blocking capacitor C6, and varactor diodes Cf, Cg, and Ch.

[0031] Each of the varactor diodes Ca, Cb, Cc, Cd, Ce, Cf, Cg, and Ch is connected to a bias; the bias is connected to the cathode of the varactor diode, and a filter inductor is connected in series between each bias and the cathode of the varactor diode. The bias voltage of each varactor diode is adjustable from 0 to 20V.

[0032] The reconfigurable bandpass filter network 5 adjusts the capacitance values ​​of varactor diodes Cc, Cd, Ce, Cf, Cg, and Ch by applying an external bias voltage, thereby achieving continuous adjustment of the passband center frequency and bandwidth. Figure 6 , Figure 7 As shown, Figure 6 Three frequency reconfiguration bands were demonstrated: 0.95-1.35GHz, 1.25-1.65GHz, and 1.5-1.9GHz. Figure 7 Three bandwidth reconfiguration bands were demonstrated: 1.3-1.6GHz, 1.2-1.7GHz, and 1.1-1.8GHz. Each reconfigured band exhibits high selectivity, ultra-wide stopband, and strong out-of-band suppression capability.

[0033] In this configuration, TL15, the left and right ends of Tee3, TL16, the left and right ends of Tee4, and TL17 are connected in series. The left end of TL15 is connected to Curve3, and the right end of TL17 is connected to Curve5. C3, TL18, C4, TL20, and Cc are connected in series, as are TL19, C5, TL21, and Cd. The upper end of C3 is connected to the lower port of Tee3, and the upper end of TL19 is connected to the lower port of Tee4. Cc and Cd are grounded at their anodes. Ce is connected at its anode between TL19 and C5, and its cathode is connected between TL18 and C4. The generalized Chebyshev high-pass filter network 9 includes series microstrip lines TL23, TL24, TL25, and T... The microstrip lines Tee6, Tee7, Tee8, parallel short-circuited microstrip lines TL22 and TL26, DC blocking capacitor C6, varactor diodes Cf, Cg, and Ch are connected in series. The left end of Tee6 is connected to the quasi-elliptical low-pass filter network 8 with the annular symmetrical structure, the lower end is connected to TL22, and the right end is connected to the anode of Cf. The left and right ends of Tee7 are connected to the cathodes of Cf and Cg, respectively. TL23, C6, TL24, and Ch are connected in series. The upper end of TL23 is connected to the lower port of Tee7, and the anode of Ch is grounded. The left end of Tee8 is connected to the anode of Cg, the lower port is connected to TL26, and the right port is connected to the left end of TL25. The right end of TL25 is adapted to and connected to the output port 14.

[0034] Furthermore, in the reconfigurable bandpass filter network 5, microstrip lines TL15, TL16, TL17, TL18, TL19, TL20, TL21, TL22, TL23, TL24, and TL26 are all converted from inductors. Microstrip lines TL18, TL19, TL20, and TL21, together with varactor transistors Cc, Cd, and Ce, form a resonator structure unit, and microstrip lines TL23 and TL24, together with varactor transistor Ch, form a series resonant unit SR3.

[0035] In this embodiment, the resonator structure unit includes two identical series resonant units SR1 and SR2. The Miller effect introduced by the parallel varactor diode Ce can split the out-of-band transmission zeros generated by these two resonant units into two, namely TZ1 and TZ2. The series resonant unit SR3 generates an out-of-band transmission zero TZ3. TZ1 and TZ3 are respectively close to the high-frequency side and low-frequency side of the passband of the bandpass filter network, forming a highly selective adjustable bandpass, which improves the out-of-band rejection of the bandpass. TZ2 is located far away from the high-frequency side of the passband, which increases the stopband width. The reconfigurable bandpass filter network 5 adjusts the frequencies of the transmission zeros TZ1, TZ2, and TZ3 by changing the bias voltage of the varactor diodes Cc, Cd, Ce, and Ch, so as to achieve continuous adjustment of the passband center frequency and bandwidth, which has the advantages of low cost, fast tuning speed and reduced system complexity.

[0036] Furthermore, adjusting the frequency and bandwidth of the reconfigurable bandpass filter network 5 will cause changes in the input impedance curve, and the high-efficiency region of the output impedance at the drain of transistor 3 will also change with frequency. The π-type matching network 10 adjusts the capacitance values ​​of varactor diodes Ca and Cb by applying an external bias voltage, so that the input impedance curves of each reconfigurable frequency band of the reconfigurable bandpass filter network 5, after being matched by the π-type matching network 10, can completely fall into the high-efficiency impedance region of the corresponding frequency band of the drain of transistor 3, thereby achieving dynamic impedance matching between the reconfigurable bandpass filter network 5 and the drain of transistor 3. Simulation results are obtained by simulating the power amplifier, such as... Figures 8-11 Simulation results show that within the adjustable frequency range of 0.95-1.9 GHz and the adjustable bandwidth range of 1.1-1.8 GHz, all reconfigurable frequency bands can achieve efficiencies exceeding 60% and gains exceeding 10 dB. Compared to other discrete reconfigurable power amplifiers, this invention offers higher frequency adjustment flexibility and lower design complexity; compared to other continuously reconfigurable power amplifiers, this invention significantly improves the adjustable frequency range and frequency selectivity of each reconfigurable frequency band, and also boasts superior efficiency and gain.

[0037] The above-disclosed embodiments are merely preferred embodiments of the power amplifier with reconfigurable center frequency and bandwidth of the present invention. Of course, they should not be construed as limiting the scope of the present invention. Those skilled in the art will understand that all or part of the processes of the above embodiments can be implemented, and equivalent changes made in accordance with the claims of the present invention are still within the scope of the invention.

Claims

1. A power amplifier with reconfigurable center frequency and bandwidth, characterized in that, It includes an input port, an input matching network, a stabilizing network, a transistor, a dynamic impedance matching network, a varactor diode DC bias, a reconfigurable bandpass filter network, and an output port. The input port, the input matching network, the stabilizing network, the transistor, the dynamic impedance matching network, the reconfigurable bandpass filter network, and the output port are connected in sequence. The varactor diode DC bias is connected to the dynamic impedance matching network and the reconfigurable bandpass filter network, respectively. The reconfigurable bandpass filter network is composed of a cascaded ring-symmetric quasi-elliptic low-pass filter network and a generalized Chebyshev high-pass filter network. The ring-symmetric quasi-elliptic low-pass filter network includes two parallel branches symmetrically arranged vertically. These two parallel branches are formed by connecting four arc-shaped microstrip lines Curve3, Curve4, Curve5, and Curve6, and two T-shaped microstrip lines Tee2 and Tee5 in a loop. Each branch includes series microstrip lines TL15, TL16, TL17, TL18, TL19, TL20, and TL21, and a T-shaped microstrip line. The microstrip lines Tee3 and Tee4, DC blocking capacitors C3, C4, and C5, and varactor diodes Cc, Cd, and Ce are included. In the reconfigurable bandpass filter network, microstrip lines TL15, TL16, TL17, TL18, TL19, TL20, TL21, TL22, TL23, TL24, and TL26 are all converted from inductors. Microstrip lines TL18, TL19, TL20, and TL21, together with varactor diodes Cc, Cd, and Ce, form a resonator structure unit. Microstrip lines TL23 and TL24, together with varactor diode Ch, form a series resonant unit SR3.

2. The power amplifier with reconfigurable center frequency and bandwidth as described in claim 1, characterized in that, The dynamic impedance matching network includes a π-type matching network and a drain bias network. The π-type matching network includes series microstrip lines TL8, TL9, TL10, and TL11, parallel short-circuit microstrip line TL12, cross microstrip line Cross2, T-shaped microstrip line Tee1, DC blocking capacitor C2, and varactors Ca and Cb.

3. A power amplifier with reconfigurable center frequency and bandwidth as described in claim 1, characterized in that, The adjustable frequency range of the power amplifier's operating frequency band, which is reconfigurable in both center frequency and bandwidth, is 0.95 to 1.9 GHz, with a single reconfigurable frequency band bandwidth of 400 MHz; the adjustable bandwidth range is 1.1 to 1.8 GHz, with a center frequency of 1.45 GHz.

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