Four-band reconfigurable load-modulated balanced amplifier structure and regulation method thereof

Abstract

The application provides a four-frequency-band reconfigurable load modulation balanced amplifier structure and a regulation method thereof, aims to solve the problems of low efficiency during power backoff and incapability of application to multi-scene requirements in existing power amplifier technologies, and the four-frequency-band reconfigurable load modulation balanced amplifier comprises a 90 Lange coupler of input and output ports, a two-stage reconfigurable balanced power amplifier composed of an input matching network, a reconfigurable inter-stage matching network and a pre-matching network of an output stage, and a two-stage control signal power amplifier, through the combination of active load modulation technology and reconfigurable technology, the compact matching network is utilized, the efficiency during output power backoff is greatly improved, and the system requirements in different frequency-band application scenes can be met.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of radio frequency communication, in particular to a four-frequency-band reconfigurable load-modulated balanced amplifier structure and a regulating method thereof. BACKGROUND

[0002] With the wireless communication, intelligent sensing and other systems being widely applied in the national daily life and military construction field, the modern communication technology has the characteristics of large capacity, multi-carrier, multi-level, wide frequency band, high peak-to-average ratio and facing complex working environment, and the spectrum resource is tight, and so on, which puts forward higher requirements on the efficiency of power backoff, multi-working frequency band and other performances of the radio frequency power amplifier.

[0003] At present, the load modulation technology is mainly used to improve the efficiency problem at the power backoff, and the common load modulation circuit structures include the Doherty architecture and the Out-phasing architecture, but there are still problems such as unsatisfactory modulation effect, high load sensitivity and inability to apply to multi-working frequency band function. SUMMARY

[0004] In order to overcome the deficiencies of the prior art, the present application provides a four-frequency-band reconfigurable load-modulated balanced amplifier structure and a regulating method thereof. The four-frequency-band reconfigurable load-modulated balanced amplifier proposed by the present application is composed of a 90° Lange coupler, a reconfigurable balanced power amplifier and a control signal power amplifier, which combines the load-modulated balanced amplifier (LMBA) and the reconfigurable technology, controls the amplitude and phase of the control signal, so that the power amplifier has high linearity, maintains high efficiency performance at the output power backoff, meets the application requirements in different scenarios, realizes multi-function, and significantly improves the integration.

[0005] In order to achieve the above purpose, the present application provides a four-frequency-band reconfigurable load-modulated balanced amplifier structure, which comprises:

[0006] A 90° Lange coupler, a pair of reconfigurable balanced power amplifiers and a control signal power amplifier are arranged at the input port and the output port; the input end and the output end of the pair of reconfigurable balanced power amplifiers are connected between the through end and the coupled end of the 90° Lange coupler at the input port and the 90° Lange coupler at the output port; the isolation end of the 90° Lange coupler at the input port is connected to an ohmic resistance and then grounded, and the isolation end of the 90° Lange coupler at the output port is connected to the output end of the control signal power amplifier.

[0007] Preferably, the input end of the 90° Lange coupler of the input port receives the radio frequency signal, and the output end of the 90° Lange coupler of the output port outputs the radio frequency signal.

[0008] Preferably, each reconfigurable balanced power amplifier comprises: an input matching network, a reconfigurable inter-stage matching network, a pre-matching network, and bias networks corresponding to input and output stages connected in sequence.

[0009] Preferably, the reconfigurable inter-stage matching network comprises a two-stage reconfigurable bridge switched-capacitor structure and an inductor L4 connected between the two-stage reconfigurable bridge switched-capacitor structure.

[0010] The equivalent circuit of the reconfigurable bridge switched-capacitor structure of the preceding stage comprises: a capacitor C6 and a switch S1 connected in sequence, a capacitor C8 and a switch S2 connected in sequence, and the link where the capacitor C6 and the switch S1 are located is connected in parallel with the link where the capacitor C8 and the switch S2 are located; a capacitor C7 is further connected between the two links.

[0011] The equivalent circuit of the reconfigurable bridge switched-capacitor structure of the subsequent stage comprises: a capacitor C 10 and a switch S3 and a capacitor C9 connected in sequence in parallel with the capacitor C 10 .

[0012] Preferably, the working state of the switch S1 is controlled by the control signal V1 received by the gate thereof, the working state of the switch S2 is controlled by the control signal V2 received by the gate thereof, and the working state of the switch S3 is controlled by the control signal V1 received by the gate thereof.

[0013] Preferably, the input matching network adopts broadband matching to complete the impedance matching of the input end.

[0014] Preferably, the control signal power amplifier comprises: an input matching network, an inter-stage matching network, an output matching network, and bias networks corresponding to input and output stages connected in sequence.

[0015] The application also provides a control method for controlling the four-frequency reconfigurable load-modulated balanced amplifier MMIC, and the specific control steps comprise:

[0016] Adjusting the working states of the switch S1, the switch S2, and the switch S3 in the equivalent circuit corresponding to the reconfigurable balanced power amplifier or the reconfigurable main power amplifier;

[0017] Controlling the amplitude and phase of the control signal power amplifier to control the switch S1, the switch S2, and the switch S3 to work in four different frequency bands.

[0018] Preferably, if the switch S1, the switch S2 and the switch S3 are all in short circuit, input corresponding control signals to control the amplitude and phase of the control signal power amplifier, the four-frequency band reconfigurable load modulation balanced amplifier MMIC works in the first frequency band;

[0019] If the switch S1 is in open circuit, the switch S2 is in short circuit, and the switch S3 is in open circuit, input corresponding control signals to control the amplitude and phase of the control signal power amplifier, the four-frequency band reconfigurable load modulation balanced amplifier MMIC works in the second frequency band.

[0020] If the switch S1 is in short circuit, the switch S2 is in open circuit, and the switch S3 is in short circuit, input corresponding control signals to control the amplitude and phase of the control signal power amplifier, the four-frequency band reconfigurable load modulation balanced amplifier MMIC works in the third frequency band.

[0021] If the switch S1, the switch S2 and the switch S3 are all in open circuit, input corresponding control signals to control the amplitude and phase of the control signal power amplifier, the four-frequency band reconfigurable load modulation balanced amplifier MMIC works in the fourth frequency band.

[0022] The four-frequency band reconfigurable load modulation balanced amplifier structure and the regulating method thereof have the beneficial effects that:

[0023] 1. The active load modulation technology LMBA architecture is used, the amplitude control and the phase control of the control signal power amplifier are controlled, the LMBA can realize good impedance matching in the saturation and the backoff state, so that the efficiency is improved when the output power backoff, and the high linearity and the high efficiency performance in multiple power modes are achieved.

[0024] 2. The reconfigurable matching network is added between the balanced power amplifier stages, the working states of the switch S1, the switch S2 and the switch S3 are adjusted through the two independent control signals V1 and V2, and the four-frequency band working function can be realized. The single wideband is discretized into multiple narrowbands through the reconfigurable switch technology, and the gain of the LMBA and the efficiency of the front-stage power amplifier are improved.

[0025] 3. The pre-matching structure is added to the output network of the balanced power amplifier, so that the balanced power amplifier is closer to the optimal load impedance point under the condition of large power output, and the load modulation effect under the condition of high-frequency large power output is more easily realized by setting the power ratio of the load modulation in a reasonable range.

[0026] 4. The 90° Lange coupler, the two-stage reconfigurable balanced power amplifier and the two-stage control signal power amplifier are integrated by combining the LMBA technology with the reconfigurable technology, and the multifunctionalization is achieved.

[0027] 5. Power distribution and synthesis are performed using a 90° Lange coupler. The reflected signals will be completely canceled at the input and output ports, achieving good reflection coefficients at the input and output over a wide frequency range, while also exhibiting excellent load insensitivity. Attached Figure Description

[0028] Figure 1 This invention provides a schematic diagram of a four-band reconfigurable load modulation balanced amplifier structure.

[0029] Figure 2 A reconfigurable inter-level matching network and its equivalent schematic diagram are provided in one embodiment of the present invention;

[0030] Figure 3 This is a schematic diagram of the Lange coupler in one embodiment of the present invention;

[0031] Figure 4 A schematic diagram of a four-band reconfigurable load modulation balanced amplifier structure constructed in one embodiment of the present invention;

[0032] Figure 5 A schematic diagram of the structure of a complete four-band reconfigurable load modulation balanced amplifier formed by cascading circuits, provided in one embodiment of the present invention.

[0033] Figure 6 The simulation performance diagrams of the small-signal gain, input reflection coefficient, and output reflection coefficient of the four-band reconfigurable load modulation balanced amplifier provided in the embodiments of the present invention are shown.

[0034] Figure 7 The simulation performance graphs of the power-added efficiency versus output power relationship of an embodiment of the structure provided by the present invention at 8GHz, 8.7GHz, 9.8GHz, and 10.8GHz are shown. Detailed Implementation

[0035] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that, unless otherwise specified, the following embodiments and features described therein can be combined with each other.

[0036] like Figure 1As shown, the application provides a four-band reconfigurable load modulation balanced amplifier structure, which comprises: a 90° Lange coupler arranged at an input port and an output port, a pair of reconfigurable balanced power amplifiers, and a control signal power amplifier; the input and output ends of the pair of reconfigurable balanced power amplifiers are connected between the through end and the coupled end of the 90° Lange coupler at the input port and the 90° Lange coupler at the output port, respectively; the isolation end of the 90° Lange coupler at the input port is connected to an ohmic resistance and then grounded, and the isolation end of the 90° Lange coupler at the output port is connected to the output end of the control signal power amplifier.

[0037] Specifically, the input port of the 90° Lange coupler at the input port is used as a radio frequency input, the isolation port is connected to a 50-ohm resistance, and the through port and the coupled port are respectively connected to two input ends of the reconfigurable balanced power amplifier; the output port of the 90° Lange coupler at the output port is used as a radio frequency output, the isolation port is connected to the output end of the control signal power amplifier, and the through port and the coupled port are respectively connected to two output ends of the reconfigurable balanced power amplifier.

[0038] The application utilizes the LMBA architecture, adds a pre-matching network structure at the output end of the balanced power amplifier or the main power amplifier, so that it is closer to the optimal load impedance point under the condition of larger power output, thereby making the load modulation effect under the condition of larger power output more easily realized. Meanwhile, the reconfigurable switch technology is added in the design of the inter-stage matching network of the balanced power amplifier or the main power amplifier, so that four different inter-stage impedances are formed, thereby dividing the working frequency band into four regions, improving the efficiency of the front-stage power amplifier and the overall gain, and further improving the efficiency of the front-stage power amplifier and the overall gain; in addition, the input end utilizes wideband matching to complete input matching, so that it can meet all working frequency bands, thereby maximizing the gain; the reconfigurable balanced power amplifier is constructed through the pre-matching network, the reconfigurable inter-stage matching network, and the wideband input matching network.

[0039] In the application, each reconfigurable balanced power amplifier comprises: an input matching network, a reconfigurable inter-stage matching network, a pre-matching network, and bias networks corresponding to the input and output stages, which are connected in sequence.

[0040] The input matching network comprises resistors R1, a microstrip line TL1, a capacitor C1, an inductor L1, a capacitor C2, an inductor L2, a capacitor C3, a resistor R2, and an inductor L3, which are connected in sequence; the input matching network adopts wideband matching to complete impedance matching of the input end, so that it can meet all working frequency bands, thereby maximizing the gain.

[0041] The reconfigurable inter-stage matching network comprises two-stage reconfigurable bridge switched capacitor structures symmetrically arranged and an inductor L4 connected between the two-stage reconfigurable bridge switched capacitor structures. 10 The control terminal of the switch M4 receives the control signal V2.

[0042] The circuit of the reconfigurable bridge switched capacitor structure of the front stage can be equivalent to a capacitor C6 and a switch S1 connected in sequence, a capacitor C8 and a switch S2 connected in sequence, and the link in which the capacitor C6 and the switch S1 are located being connected in parallel with the link in which the capacitor C8 and the switch S2 are located. 10 The circuit of the reconfigurable bridge switched capacitor structure of the back stage can be equivalent to a capacitor C 10 and a switch S3 and a capacitor C9 connected in sequence in parallel. The resistor R3, the switch M2 and the resistor R4 can be equivalent to the switch S1, the resistor R5, the switch M3 and the resistor R6 can be equivalent to the switch S2, and the resistor R7, the switch M4 and the resistor R8 can be equivalent to the switch S3. The working state of the switch S1 is controlled by the control signal V1 received by the gate thereof, the working state of the switch S2 is controlled by the control signal V2 received by the gate thereof, and the working state of the switch S3 is controlled by the control signal V1 received by the gate thereof. By adjusting the working states of the switches S1, S2 and S3 through two independent control signals V1 and V2, the function of working in four frequency bands can be realized. By means of the reconfigurable switch technology, a single wideband is discretized into multiple narrowbands, and the gain and efficiency of the LMBA are improved in combination with two-stage power amplifiers.

[0043] In the present application, the pre-matching network is arranged in the output stage, which comprises a microstrip line capacitor C 13 , a capacitor C 14 , a microstrip line TL5, a microstrip line capacitor C 13 and a capacitor C 14One end of the connection is connected to the inductor L6 and then to the ground. The output network of the balanced power amplifier is added with a pre-matching structure, so that it is closer to the optimal load impedance point under the condition of large power output, and the power ratio of the load modulation is set in a reasonable range, so that the load modulation effect under the condition of high frequency and large power output is more easily achieved.

[0044] In the bias network of the input stage, the drive tube is composed of a single transistor M1, the bias network of the gate includes resistors R2, inductors L3, capacitors C4 and gate voltage V g1 in sequence, and the bias network of the drain includes microstrip lines TL2, capacitors C5 and gate voltage V d1 in sequence. In the bias network of the output stage, the amplification tube is composed of transistors M5 and M6 in parallel, the bias network of the gate of the two includes resistors R9, inductors L5, capacitors C 11 and gate voltage V g2 in sequence, and the bias network of the drain of the two includes microstrip lines TL4, capacitors C 12 and gate voltage V d2 in sequence.

[0045] In the present application, the control signal power amplifier is composed of a two-stage circuit, including a signal input matching network, an inter-stage matching network, an output matching network, and the corresponding bias networks of the input stage and the output stage connected in sequence.

[0046] The signal input matching network includes resistors R 10 , microstrip lines TL6, capacitors C 15 , microstrip lines TL7 and capacitors C 16 connected in sequence. The inter-stage matching network includes microstrip lines TL9, capacitors C 19 , inductors L8 and capacitors C 20 connected in sequence. The output matching network includes capacitors C 23 , inductors L 10 , capacitors C 24 and microstrip lines TL 11 connected in sequence. In the bias network of the input stage of the control signal power amplifier, the drive tube is composed of a single transistor M7, the bias network of the gate includes resistors R 11 , inductors L7, capacitors C 17 and gate voltage V g3 connected in sequence, and the bias network of the drain includes microstrip lines TL8, capacitors C 18 and gate voltage V d3 connected in sequence. In the bias network of the output stage, the amplification tube includes two transistors M8 and M9 in parallel, the bias network of the gate of the two includes resistors R 12 , inductors L9, capacitors C21 , the gate voltage V g4 , the bias network of the two drain electrodes comprises a microstrip line TL 10 , the capacitance C 22 , the gate voltage V d4 .

[0047] The control signal power amplifier outputs a power signal to the isolation end of the Lange coupler by modulating the input signal, and adjusts the amplitude and phase of the control signal power amplifier input signal, so as to complete the load modulation of the balanced power amplifier, so that the balanced power amplifier still maintains high efficiency performance when the output power backoff. In addition, the control signal power amplifier has wideband and high efficiency performance, and can meet the modulation of four operating frequency bands. The control signal power amplifier can restore power at the output end through the Lange coupler, thereby improving the total efficiency by improving the efficiency of the control signal power amplifier.

[0048] The application also provides a control method for controlling the four-frequency-band reconfigurable load-modulated balanced amplifier MMIC, and the specific control steps include:

[0049] Adjusting the working states of the switches S1, S2 and S3 in the equivalent circuit corresponding to the reconfigurable balanced power amplifier or the reconfigurable main power amplifier;

[0050] Controlling the amplitude and phase of the control signal power amplifier, and controlling the switches S1, S2 and S3 to work in four different frequency bands, so as to maintain high efficiency performance when the output power backoff.

[0051] The specific control mode includes:

[0052] If the switches S1, S2 and S3 are all in short circuit, and the amplitude and phase of the control signal power amplifier are controlled by inputting corresponding control signals, the four-frequency-band reconfigurable load-modulated balanced amplifier MMIC works in the first frequency band.

[0053] If the switch S1 is in open circuit, the switch S2 is in short circuit, and the switch S3 is in open circuit, and the amplitude and phase of the control signal power amplifier are controlled by inputting corresponding control signals, the four-frequency-band reconfigurable load-modulated balanced amplifier MMIC works in the second frequency band.

[0054] If the switch S1 is in short circuit, the switch S2 is in open circuit, and the switch S3 is in short circuit, and the amplitude and phase of the control signal power amplifier are controlled by inputting corresponding control signals, the four-frequency-band reconfigurable load-modulated balanced amplifier MMIC works in the third frequency band.

[0055] If the switches S1, S2 and S3 are all in open circuit, input corresponding control signals to control the amplitude and phase of the control signal power amplifier, then the four-frequency reconfigurable load modulation balanced amplifier MMIC works in the fourth frequency band.

[0056] If the open circuit and short circuit states of the switches S1, S2 and S3 are controlled by the switching of the control signals V1 and V2, the control method specifically includes:

[0057] If the control signal V1 is high and the control signal V2 is high, the four-frequency reconfigurable load modulation balanced amplifier MMIC works in the first frequency band.

[0058] If the control signal V1 is low and the control signal V2 is high, the four-frequency reconfigurable load modulation balanced amplifier MMIC works in the second frequency band.

[0059] If the control signal V1 is high and the control signal V2 is low, the four-frequency reconfigurable load modulation balanced amplifier MMIC works in the third frequency band.

[0060] If the control signal V1 is low and the control signal V2 is low, the four-frequency reconfigurable load modulation balanced amplifier MMIC works in the fourth frequency band.

[0061] Based on the four-frequency reconfigurable load modulation balanced amplifier structure, the application provides a design example of the four-frequency reconfigurable load modulation balanced amplifier structure, and the specific design steps include:

[0062] S1: Design of reconfigurable balanced power amplifier.

[0063] The balanced power amplifier includes two completely symmetrical links, and due to the 90° Lange coupler at the input and output ends, the reflection signals of the two links are completely canceled at the input and output ports, so that the input and output have good reflection coefficient in a wide frequency band range, and the load sensitivity is reduced. The design of the reconfigurable balanced power amplifier needs to comprehensively consider the performances of power, efficiency, gain, stability, reconfigurability, modulation effect and the like, select appropriate transistors, operating voltages and circuit topological structures, including the design of transistor sizes, output stage pre-matching network, reconfigurable inter-stage matching network, input matching network and bias network of each stage.

[0064] S1.1: Design of transistor sizes of each stage.

[0065] The design of transistor sizes needs to consider the performances of output power, driving power and gain.

[0066] In this embodiment, the (output stage) later stage transistor adopts two total gate widths of 400 um in parallel to increase the output power and provide a certain size of gain, and the (input stage) front stage transistor adopts a single total gate width of 400 um to provide sufficient driving power and provide sufficient gain.

[0067] S1.2: Design of the pre-matching network of the output stage.

[0068] The conventional LMBA is not matched in the output stage of the balanced power amplifier, and is directly connected with the Lange coupler at the output end. In the high-frequency and high-power design, a large control signal needs to be injected for load modulation, which affects the efficiency of the overall circuit. Through the pre-matching structure of the output stage of the balanced power amplifier, it is closer to the optimal load impedance point under the condition of larger power output, so that the load modulation effect under the condition of high-frequency and large power output is more easily achieved.

[0069] In this embodiment, the optimal impedance value under the condition of larger power in the required working frequency band is measured by the load dragging output stage transistor, and the capacitance C 13 , the inductance L6, and the capacitance C 14 form a double-L type topology structure and are matched in series with the microstrip line TL5 to about 30 ohms, which can be close to the optimal impedance under the condition of larger power under different working frequencies.

[0070] S1.3: Design of the reconfigurable inter-stage matching network.

[0071] The design of the reconfigurable inter-stage matching network needs to consider the matching difficulty, efficiency, gain, modulation effect, and other performances. The single wideband is discretized into multiple narrowbands by using the reconfigurable switch technology, so as to divide the working frequency band into four regions, thereby improving the gain and the efficiency of the front stage.

[0072] In this embodiment, as shown in Figure 2 , it is the reconfigurable inter-stage matching network and the equivalent schematic diagram, wherein the resistors R3, R4, R5, R6, R7, and R8 are used to provide 0 potential for the source and drain of the switch tube, the resistor R3, the switch tube M2, and the resistor R4 can be equivalent to the switch S1, the resistor R5, the switch tube M3, and the resistor R6 can be equivalent to the switch S2, and the resistor R7, the switch tube M4, and the resistor R8 can be equivalent to the switch S3.

[0073] The reconfigurable inter-stage matching network can provide four kinds of impedances to correspond to the frequencies under the four working states of the power amplifier. The first frequency band is 7.8-8.2 GHz, the second frequency band is 8.5-8.9 GHz, the third frequency band is 9.6-10 GHz, and the fourth frequency band is 10.6-11 GHz, which are represented by f1, f2, f3, and f4 respectively.

[0074] When switch S1 is in short circuit, switch S2 is in short circuit, and switch S3 is in short circuit, impedance Z1 can be expressed as:

[0075]

[0076] Wherein, j is the imaginary unit, C 6～10 is the capacitance value of capacitor C6-C 10 , and L4 is the inductance value of inductor L4.

[0077] When switch S1 is in open circuit, switch S2 is in short circuit, and switch S3 is in open circuit, impedance Z2 can be expressed as:

[0078]

[0079] When switch S1 is in short circuit, switch S2 is in open circuit, and switch S3 is in short circuit, impedance Z3 can be expressed as:

[0080]

[0081] When switch S1 is in open circuit, switch S2 is in open circuit, and switch S3 is in open circuit, impedance Z4 can be expressed as:

[0082]

[0083] S1.4: Input matching network design.

[0084] The design of the input matching network needs to meet the broadband matching and port matching to maximize the gain.

[0085] In this embodiment, the input matching adopts multi-branch broadband matching, which is composed of resistance R1, microstrip line TL1, capacitor C1, inductor L1, capacitor C2, inductor L2, capacitor C3, resistance R2, inductor L3 connected in sequence. Among them, the resistance R1 can increase the real part of the input impedance, reduce the matching difficulty, and increase the circuit stability. The input matching composed of resistance, inductor, capacitor and microstrip line can realize the conjugate matching with the through port and the coupling port of the coupler, and reduce the gain loss of the power amplifier.

[0086] S1.5: Design of bias network corresponding to input stage and output stage.

[0087] The design of the bias network corresponding to the input stage and the output stage needs to consider the transistor operating characteristics and circuit stability to ensure that the circuit can work normally.

[0088] In this embodiment, the front-stage (input stage) driving tube is composed of a single transistor M1, the gate bias network is composed of resistance R2, inductor L3, capacitor C4, gate voltage V g1 connected in sequence, and the drain bias network is composed of microstrip line TL2, capacitor C5, gate voltage Vd1 The components are connected sequentially. The output stage amplifier consists of two transistors, M5 and M6, connected in parallel. The gate bias network consists of resistor R9, inductor L5, and capacitor C. 11 , gate voltage V g2 The components are connected sequentially, and the subsequent drain bias network consists of microstrip line TL4 and capacitor C. 12 , gate voltage V d2 The circuit is assembled sequentially. The resistors in each bias network stage increase the circuit's low-frequency stability. Inductors L3, microstrip line TL2, inductors L5, and TL4 suppress AC signal leakage (the microstrip line is theoretically chosen to be a quarter wavelength, achieving the effect of DC short circuit and fundamental open circuit). The parallel capacitors C4, C5, and C6... 11 C 12 It can filter out interference signals from voltage sources, and both stages of transistors are biased in deep Class AB operating mode.

[0089] Step 2: Design of the control signal power amplifier.

[0090] Control signal power amplifiers need to have high efficiency to improve the overall power amplifier efficiency. They also need to consider performance characteristics such as bandwidth, power, gain, stability, and modulation effect, and select appropriate transistors, operating voltages, and circuit topologies, including the design of transistor sizes at each stage, output matching networks, inter-stage matching networks, input matching networks, and bias networks at each stage.

[0091] In this embodiment, the control signal power amplifier is designed as a two-stage broadband high-efficiency power amplifier ranging from 7.5 to 11.5 GHz. The output stage uses two transistors with a total gate width of 400 μm connected in parallel to increase output power and provide a certain amount of gain. The input stage uses a single transistor with a total gate width of 400 μm to provide sufficient drive power and gain. The output matching network is connected to the isolation terminal of the Lange coupler in the output stage, achieving optimal load impedance matching with the port of the output stage transistor. The inter-stage matching network achieves optimal load impedance matching between the input stage transistor and the output stage transistor, maximizing efficiency. The input matching network constructs a broadband matching network, achieving conjugate matching with the port and reducing gain loss. Each stage bias network includes resistors to increase stability, inductors / microstrip lines to prevent signal leakage, and capacitors to filter interference signals. Both stages of transistors are biased in deep Class AB operation. The control signal power amplifier serves both as a load modulator and an active matching mechanism.

[0092] Step 3: Design of the 90° Lange coupler.

[0093] like Figure 3As shown, it is a 90° Lange coupler structure, which is composed of 4 ports, port 1 is the input port, port 2 is the through port, port 3 is the isolation port, and port 4 is the coupling port, and the through port and the coupling port have a 90° phase difference.

[0094] In this embodiment, the microstrip line is used for the design of the Lange coupler, the working frequency band is controlled by adjusting the length L of the coupler, the coupling strength and the through loss are controlled by adjusting the spacing S and the line width W (the line width of the latter coupler needs to consider the power bearing capacity), so that the working frequency band contains 7.5-12 GHz, and the coupling strength and the through loss are both close to 3dB. The input port of the 90° Lange coupler of the input port is used as the radio frequency input, the isolation port is connected to a 50 ohm resistor, and the through port and the coupling port are respectively connected to the two input ends of the balanced power amplifier, which can be used to divide the input power equally. The output port of the 90° Lange coupler of the output port is used as the radio frequency output, the isolation port is connected to the output end of the control signal power amplifier, and the through port and the coupling port are respectively connected to the two output ends of the balanced power amplifier, which can be used to balance the output power of the balanced power amplifier and the synthesis of the control power amplifier output power.

[0095] Step 4: Connect the 90° Lange coupler of the input and output ports, the reconfigurable balanced power amplifier and the control signal power amplifier to obtain a complete four-frequency band reconfigurable load modulation balanced amplifier for debugging and optimization, as shown in Figure 4 , which is a four-frequency band reconfigurable load modulation balanced amplifier structure.

[0096] Among them, the 90° Lange coupler structure of the output port, port 2 and port 4 are input ports, port 3 is an isolation port, and port 1 is an output port. The Z matrix corresponding to the four ports and the voltage and current relationship are:

[0097]

[0098] Port 4 and port 2 correspond to the equivalent current sources I4 and I2 of the reconfigurable balanced power amplifier, and the control power amplifier of the isolation port 3 is equivalent to a current source I3. 1～4 V is the equivalent voltage corresponding to ports 1-4. b1 Z and Z b2 are the input port impedance, Z0 is the characteristic impedance of the coupler, and the output current amplitudes of the reconfigurable balanced power amplifier are equal, and the phase difference is 90 degrees, that is, I4=-I b , I2=-jI b , j is the imaginary unit, and I b represents the current amplitudes of ports 2 and 4, and the current amplitude of port 3 is I c , and the phase difference between the output current I2 and the output current I2 is φ, I3=-jI c ejφ The port impedance can be expressed as:

[0099]

[0100] According to the above formula, the load impedance of the load-modulated balanced amplifier can be modulated by the amplitude ratio and phase difference of the control signal power amplifier and the main power amplifier output current, which can theoretically cover the entire Smith chart. The power P b1 of port 1, b2 and the power P cs injected into the isolated port of the Lange coupler can be expressed as:

[0101]

[0102]

[0103] Theoretically, the power P cs injected into the isolated port of the Lange coupler can be completely recovered at the output port of the Lange coupler, and the total output power P out can be expressed as:

[0104] P out = P b1 + P b2 + P cs ......(9),

[0105] Define the power ratio factor β of the control signal power amplifier and the single-branch balanced power amplifier:

[0106]

[0107] The reflection coefficient ρ from port 2 or port 4:

[0108]

[0109] From (10) and (11), we have:

[0110]

[0111] The power ratio factor β of the control signal and the main signal can be mapped on a set of reflection coefficient circles, representing the position of the load impedance modulation. When the power ratio factor β is constant, the corresponding reflection coefficient is on a circle with a radius of , and the center is the origin of the Smith chart. When the power phase difference θ of the control signal power amplifier and the balanced power amplifier increases, the reflection coefficient rotates counterclockwise on the circle. Based on the power ratio factor β and the phase difference θ, amplitude modulation and phase modulation can be achieved.

[0112] In this embodiment, the cascaded circuits yield a complete four-band reconfigurable load-modulated balanced amplifier, such as... Figure 5 As shown, the overall circuit performance is simulated and the pre-matching network, reconfigurable inter-stage matching network, input matching network, and each stage bias network of the reconfigurable balanced power amplifier are optimized respectively, as well as the output matching network, inter-stage matching network, input matching network, and each stage bias network of the auxiliary power amplifier. The optimization is continuously iterated and optimized to obtain the optimal value of each device.

[0113] In accordance with the above embodiments, the present invention also provides a method for controlling a four-band reconfigurable load modulation balanced amplifier. The steps include: controlling the open-circuit and short-circuit states of switches S1 and S3 via control signal V1; controlling the open-circuit and short-circuit states of switch S2 by switching the high and low levels of control signal V2; adjusting the operating states of switches S1, S2, and S3; and controlling the amplitude and phase of the power amplifier via control signals to enable it to operate in four different frequency bands while maintaining high efficiency performance during output power back-off.

[0114] like Figure 6 The figure shows the simulation performance of the small-signal gain, input reflection coefficient, and output reflection coefficient of the four-band reconfigurable load modulation balanced amplifier.

[0115] Combining the amplitude control, phase control, and switching control strategies from simulation, the input signal RF in Scan from -2dBm to 13dBm, with 1dBm intervals, control signal CS in Scan from -5dBm to 13dBm, with an interval of 1dBm; scan the phase from 0 degrees to 360 degrees, with an interval of 10 degrees; adjust control signals V1 and V2 to make them work in different frequency bands.

[0116] like Figure 7 The figures show the simulated performance of the power-added efficiency versus output power at 8 GHz, 8.7 GHz, 9.8 GHz, and 10.8 GHz, respectively. The point where the power-added efficiency is maximized at each output power is the optimal modulation effect at that output power. Compared with the efficiency at the normalized ideal Class B power amplifier output power down by 6 dB, it has a 6% efficiency improvement at 8 GHz, a 10% efficiency improvement at 8.7 GHz, a 15% efficiency improvement at 9.8 GHz, and a 13% efficiency improvement at 10.8 GHz.

[0117] Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

Claims

1. A quad-band reconfigurable load-modulated balanced amplifier architecture, characterized by, The application relates to a four-frequency-band reconfigurable load-modulated balanced amplifier MMIC. The four-frequency-band reconfigurable load-modulated balanced amplifier MMIC comprises a 90-degree Lange coupler arranged at an input port and an output port, a pair of reconfigurable balanced power amplifiers, and a control signal power amplifier. The input end and the output end of the pair of reconfigurable balanced power amplifiers are connected between the through end and the coupled end of the 90-degree Lange coupler at the input port and the 90-degree Lange coupler at the output port; the isolation end of the 90-degree Lange coupler at the input port is connected to an ohmic resistance and then grounded, and the isolation end of the 90-degree Lange coupler at the output port is connected to the output end of the control signal power amplifier. The input end of the 90-degree Lange coupler at the input port receives a radio frequency signal, and the output end of the 90-degree Lange coupler at the output port outputs the radio frequency signal. Each reconfigurable balanced power amplifier comprises an input matching network, a reconfigurable inter-stage matching network, a pre-matching network, and bias networks corresponding to the input stage and the output stage which are sequentially connected. The reconfigurable inter-stage matching network comprises a two-stage reconfigurable bridge-type switched capacitor structure and an inductor L4 connected between the two-stage reconfigurable bridge-type switched capacitor structure. The equivalent circuit of the front-stage reconfigurable bridge-type switched capacitor structure comprises a capacitor C6 and a switch S1 which are sequentially connected, a capacitor C8 and a switch S2 which are sequentially connected, and the link where the capacitor C6 and the switch S1 are located is connected in parallel with the link where the capacitor C8 and the switch S2 are located; a capacitor C7 is further connected between the two links. The equivalent circuit of the reconfigurable bridge type switched capacitor structure of the latter stage comprises a capacitor C 10 and a switch S3 and a capacitor C9 connected in sequence in parallel with the capacitor C 10 ​ The working state of the switch S1 is controlled by a control signal V1 received by the gate of the switch S1, the working state of the switch S2 is controlled by a control signal V2 received by the gate of the switch S2, and the working state of the switch S3 is controlled by a control signal V1 received by the gate of the switch S3.

2. The quad-band reconfigurable load-modulated balanced amplifier structure of claim 1, wherein, The input matching network adopts wideband matching to complete the impedance matching of the input end.

3. The quad-band reconfigurable load-modulated balanced amplifier structure of claim 1, wherein, The control signal power amplifier comprises an input matching network, an inter-stage matching network, and an output matching network which are sequentially connected, and bias networks corresponding to the input stage and the output stage.

4. A method for regulating a quad-band reconfigurable load-modulated balanced amplifier MMIC according to any one of claims 1-3, characterized by, The specific regulation steps comprise: adjusting the working states of the switches S1, S2 and S3 in the equivalent circuit corresponding to the reconfigurable balanced power amplifier or the reconfigurable main power amplifier; controlling the amplitude and the phase of the control signal power amplifier and controlling the switches S1, S2 and S3 to work in four different frequency bands.

5. The regulation method according to claim 4, wherein if the switches S1, S2 and S3 are all in short circuit, the four-frequency-band reconfigurable load-modulated balanced amplifier MMIC works in the first frequency band by inputting corresponding control signals to regulate the amplitude and the phase of the control signal power amplifier; if the switch S1 is in open circuit, the switch S2 is in short circuit, and the switch S3 is in open circuit, the four-frequency-band reconfigurable load-modulated balanced amplifier MMIC works in the second frequency band by inputting corresponding control signals to regulate the amplitude and the phase of the control signal power amplifier; if the switch S1 is in short circuit, the switch S2 is in open circuit, and the switch S3 is in short circuit, the four-frequency-band reconfigurable load-modulated balanced amplifier MMIC works in the third frequency band by inputting corresponding control signals to regulate the amplitude and the phase of the control signal power amplifier. ​ If the switch S1, the switch S2 and the switch S3 are all in open circuit, input corresponding control signals to control the amplitude and phase of the control signal power amplifier, then the four-frequency reconfigurable load-modulated balanced amplifier MMIC works in the fourth frequency band.

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