Detailed Description
In the following description, for purposes of explanation and not limitation, specific details are set forth, such as particular system structures, techniques, etc. in order to provide a thorough understanding of the embodiments of the invention. It will be apparent, however, to one skilled in the art that the present invention may be practiced in other embodiments that depart from these specific details. In other instances, detailed descriptions of well-known systems, devices, circuits, and methods are omitted so as not to obscure the description of the present invention with unnecessary detail.
In order to explain the technical scheme of the invention, the performance index of the multi-channel multifunctional chip is explained below.
The important performance indexes of the multi-channel multifunctional chip are as follows:
1. the working frequency is as follows: generally, the frequency band is an operating frequency band, such as 14 GHz-18 GHz, 19 GHz-23 GHz, 29 GHz-31 GHz, etc.
2. Gain: the amplification capability of the chip to the signal can be expressed as output power to input power, i.e. gin ═ Pout/Pin.
3. Input-output voltage standing wave ratio: the degree of reflection of the input/output port signal may be expressed by the degree of port mismatch, i.e., VSWR (1+ | Γ |)/(1- | Γ |), where Γ is the voltage reflection coefficient of the port.
4. Phase shift digit, phase shift step and phase shift range: the phase-shifting digit is 6, the phase-shifting step is 5.625 degrees, the total number of 63 phase-shifting states is 63, and the phase-shifting range is 5.625-354.375 degrees.
5. Relative phase shift quantity: the relative phase shift amount of each phase-shifted state is PSi ═ phase (S21 for the corresponding phase-shifted state) -phase (S21 for the reference state) |.
6. Phase shift precision: the phase-shifting precision of each phase-shifted state is delta phi i-PSi-the nominal value of the corresponding phase-shifted state
7. Phase-shift root mean square error:
wherein n is 63.
8. Amplitude consistency among channels:
gain Gi ═ dB in the reference state of each channel (S21 in the reference state) i, i ═ 1,2,3, …, n;
the amplitude consistency among the channels refers to the gain consistency among different channels of the same tested chip under the same frequency in a reference state, namely, Δ Am is max (G1, G2, G3, …, Gn) -min (G1, G2, G3, …, Gn).
9. Phase consistency among channels:
phase PHi ═ phase (S21 for reference state) i |, i ═ 1,2,3, …, n for each channel reference state;
the phase consistency among the channels refers to the phase consistency among different channels of the same tested chip under the same frequency, and Δ φ n is max (PH1, PH2, PH 3, …, PH n) -min (PH1, PH2, PH 3, …, PH n).
Note 1: dB () is a function that converts the magnitude-phase form of the S parameter to decibel representation.
Note 2: phase () is a function that converts the amplitude-phase form of the S-parameter to a phase representation.
Note 3: and 2 and 1 in the S parameters correspond to an output port and an input port of the tested chip during testing.
Note 4: the reference state refers to a state in which no phase shift is performed.
In the TR component, an input port of a multifunctional chip is connected with an output port of a low-noise amplifier chip in most cases, and an output port of the multifunctional chip is connected with an input port of a power amplifier chip; in order to reduce the loss of energy transfer between the chips as much as possible, the port butted between the chips is required to have a good voltage standing wave ratio. The invention provides an optimization method which can improve the voltage standing wave ratio of a multifunctional chip. In order to explain the technical means of the present invention, the following description will be given by way of specific examples.
Fig. 1 is a schematic circuit diagram of a four-channel multifunctional chip according to an embodiment of the present invention. As shown in fig. 1, a four-channel multifunction chip of this embodiment includes:
an input end RFin of the multifunctional chip, four output ends RFout1-RFout4 of the multifunctional chip, and a power supply end V of the multifunctional chipEEThe multi-functional chip comprises a grounding end GND, an amplifier, a grid end power supply end VG, a drain end power supply end VD, a one-to-four power divider, four phase shifters, three serial-parallel drivers, a DATA latch end LD, a DATA input end DATA, a clock end CLK and a chip selection end CS;
the four outputs of the multifunctional chip include a first output RFout1 of the multifunctional chip, a second output RFout2 of the multifunctional chip, a third output RFout3 of the multifunctional chip, and a fourth output RFout4 of the multifunctional chip;
the four phase shifters comprise a first phase shifter, a second phase shifter, a third phase shifter and a fourth phase shifter;
the three serial-to-parallel drivers comprise a first serial-to-parallel driver, a second serial-to-parallel driver and a third serial-to-parallel driver;
the amplifier is respectively connected with an input end RFin, a grid end power supply end VG, a drain end power supply end VD and a one-to-four power divider of the multifunctional chip;
the four-in-one power divider is respectively connected with a first phase shifter, a second phase shifter, a third phase shifter and a fourth phase shifter, the first phase shifter is connected with a first output end RFout1 of the multifunctional chip, the second phase shifter is connected with a second output end RFout2 of the multifunctional chip, the third phase shifter is connected with a third output end RFout3 of the multifunctional chip, and the fourth phase shifter is connected with a fourth output end RFout4 of the multifunctional chip;
the first serial-to-parallel driver is respectively connected with the second serial-to-parallel driver, the third serial-to-parallel driver and the power supply end V of the multifunctional chipEEThe second serial-to-parallel driver is connected with the third serial-to-parallel driver;
the third serial-parallel driver is connected with the first phase shifter and the second phase shifter, and the second serial-parallel driver is connected with the third phase shifter and the fourth phase shifter;
at least one of the first phase shifter, the second phase shifter, the third phase shifter and the fourth phase shifter includes a phase shift functional module including at least an attenuation circuit.
In one embodiment, the amplifier amplifies an input signal input through an input terminal RFin of the multifunction chip, the amplified input signal is distributed to a first phase shifter, a second phase shifter, a third phase shifter and a fourth phase shifter through a 1-4-division power divider, and the first phase shifter, the second phase shifter, the third phase shifter and the fourth phase shifter process the respective amplified input signals, wherein the phase shifters are in a digital control mode, the phase shift is performed by 5.625 °, and the phase shift range is 0 ° to 354.375 °.
Further, the first serial-parallel driver, the second serial-parallel driver and the third serial-parallel driver form a 24-serial-parallel driver, 24 paths of 0V/-5V complementary voltages are output, and 0V or-5V voltages are respectively provided for gates of the PHEMT devices in the four phase shifters. The first cascode driver is connected to external input terminals (a DATA latch terminal LD, a DATA input terminal DATA, a clock terminal CLK, and a chip select terminal CS) to implement input level shift and single-ended to differential functions. The second serial-to-parallel driver and the third serial-to-parallel driver are both 12-bit serial-to-parallel driver circuits, share a clock and latch, are cascaded to form a 24-bit serial-to-parallel driver circuit, and realize conversion from 24-bit serial codes to parallel codes at a specified time sequence; an input signal of a clock end CLK enters a first serial-parallel driver to generate differential signals 1 and 2 which are respectively input into a second serial-parallel driver and a third serial-parallel driver; an input signal of the data latch end LD enters a first serial-parallel driver to generate differential signals 3 and 4 which are respectively input into a second serial-parallel driver and a third serial-parallel driver; the input signal at DATA input terminal DATA enters the first deserializer driver to generate differential signals 5 and 6, enters the second deserializer driver, is output serially by the second deserializer driver to generate signals 7 and 8, and enters the third deserializer driver. The input signal of the chip select terminal CS enters the first cascode driver and performs a logic operation with the input signal of the clock terminal CLK to control the input signal of CLK.
In an embodiment, the attenuation circuit in the phase shift functional module arranged in at least one of the first phase shifter, the second phase shifter, the third phase shifter and the fourth phase shifter can effectively improve the voltage standing wave ratio of the output port connected with the corresponding phase shifter, so as to improve the performance of the multi-channel multifunctional chip.
The four-channel multifunctional chip of the embodiment of the invention comprises: the circuit comprises an input end of a multifunctional chip, four output ends of the multifunctional chip, a power supply end of the multifunctional chip, a grounding end of the multifunctional chip, an amplifier, a grid end power supply end, a drain end power supply end, a one-to-four power divider, four phase shifters, three serial-parallel drivers, a data latch end, a data input end, a clock end and a chip selection end, wherein the input end of the multifunctional chip is connected with the four output ends of the multifunctional chip; at least one of the first phase shifter, the second phase shifter, the third phase shifter and the fourth phase shifter includes a phase shift functional module including at least an attenuation circuit. The phase shifter is provided with the attenuation circuit to attenuate the output signal, so that the voltage standing wave ratio of the output port connected with the phase shifter is effectively improved, and the performance of the four-channel multifunctional chip is improved.
Fig. 2 is a circuit diagram of a four-channel multifunctional chip according to another embodiment of the invention. As shown in fig. 2, a four-channel multifunction chip of this embodiment includes:
an input end RFin of the multifunctional chip, four output ends RFout1-RFout4 of the multifunctional chip, and a power supply end V of the multifunctional chipEEThe multi-functional chip comprises a grounding end GND, an amplifier, a grid end power supply end VG, a drain end power supply end VD, a one-to-four power divider, four phase shifters, three serial-parallel drivers, a DATA latch end LD, a DATA input end DATA, a clock end CLK and a chip selection end CS;
the four outputs of the multifunctional chip include a first output RFout1 of the multifunctional chip, a second output RFout2 of the multifunctional chip, a third output RFout3 of the multifunctional chip, and a fourth output RFout4 of the multifunctional chip;
the four phase shifters comprise a first phase shifter, a second phase shifter, a third phase shifter and a fourth phase shifter;
the three serial-to-parallel drivers comprise a first serial-to-parallel driver, a second serial-to-parallel driver and a third serial-to-parallel driver;
a first input end 1 of the amplifier is connected with an input end RFin of the multifunctional chip, a second input end 2 of the amplifier is connected with a grid end power supply end VG, a third input end 3 of the amplifier is connected with a drain end power supply end VD, and an output end 4 of the amplifier is connected with an input end 1 of the one-to-four power divider;
a first output end 2 of the four-way power divider is connected with a first input end 1 of a first phase shifter, and an output end 3 of the first phase shifter is connected with a first output end RFout1 of the multifunctional chip; a second output end 3 of the one-fourth power divider is connected with a first input end 1 of a second phase shifter, and an output end 3 of the second phase shifter is connected with a second output end RFout2 of the multifunctional chip; a third output end 4 of the one-fourth power divider is connected with a first input end 1 of a third phase shifter, and an output end 3 of the third phase shifter is connected with a third output end RFout3 of the multifunctional chip; a fourth output end 5 of the one-fourth power divider is connected with a first input end 1 of a fourth phase shifter, and an output end 3 of the fourth phase shifter is connected with a fourth output end RFout4 of the multifunctional chip;
the pin 1 and the pin 7 of the first cascode driver are both connected to the ground terminal GND of the multifunctional chip, the pin 2 of the first cascode driver is connected to the clock terminal CLK, and the pin 3 of the first cascode driver is connected to the power supply terminal V of the functional chipEEPin 4 of the first cascode driver is connected to the chip select terminal CS, pin 5 of the first cascode driver is connected to the DATA input terminal DATA, pin 6 of the first cascode driver is connected to the DATA latch terminal LD, pin 8 of the first cascode driver is connected to pin 12 of the second cascode driver, pin 9 of the first cascode driver is connected to pin 11 of the second cascode driver, pin 10 of the first cascode driver is connected to pin 10 of the second cascode driver, pin 11 of the first cascode driver is connected to pin 9 of the second cascode driver, pin 12 of the first cascode driver is connected to pin 8 of the second cascode driver, pin 13 of the first cascode driver is connected to pin 7 of the second cascode driver, and pin 14 of the first cascode driver is connected to pin 14 of the second cascode driverPin 6, pin 15 of the first deserializer driver is connected with pin 5 of the second deserializer driver, pin 16 of the first deserializer driver is connected with pin 5 of the third deserializer driver, pin 17 of the first deserializer driver is connected with pin 4 of the third deserializer driver, pin 18 of the first deserializer driver is connected with pin 3 of the third deserializer driver, and pin 19 of the first deserializer driver is connected with pin 2 of the third deserializer driver;
a pin 6 of the third serial-to-parallel driver is connected with a pin 4 of the second serial-to-parallel driver, and a pin 7 of the third serial-to-parallel driver is connected with a pin 3 of the second serial-to-parallel driver;
a pin 8 of the third serial-parallel driver is connected with the second input end 2 of the first phase shifter, and a pin 1 of the third serial-parallel driver is connected with the second input end 2 of the second phase shifter; pin 2 of the second serial-parallel driver is connected with the second input end 2 of the third phase shifter, and pin 1 of the second serial-parallel driver is connected with the second input end 2 of the fourth phase shifter;
at least one of the first phase shifter, the second phase shifter, the third phase shifter and the fourth phase shifter includes a phase shift functional module including at least an attenuation circuit.
In an embodiment, the connection of the third serial-parallel driver to the first phase shifter and the second phase shifter may be in the form of a plurality of wire connections, and the specific number of the wire connections is not limited. Taking the number of leads equal to 5 as an example, when the third serial-parallel driver is connected to the first phase shifter, pin 8a of the third serial-parallel driver is connected to pin 2a of the first phase shifter, pin 8b of the third serial-parallel driver is connected to pin 2b of the first phase shifter, pin 8c of the third serial-parallel driver is connected to pin 2c of the first phase shifter, pin 8d of the third serial-parallel driver is connected to pin 2d of the first phase shifter, and pin 8e of the third serial-parallel driver is connected to pin 2e of the first phase shifter. Under the condition that the third serial-parallel driver is connected with the second phase shifter, a pin 1a of the third serial-parallel driver is connected with a pin 2a of the second phase shifter, a pin 1b of the third serial-parallel driver is connected with a pin 2b of the second phase shifter, a pin 1c of the third serial-parallel driver is connected with a pin 2c of the second phase shifter, a pin 1d of the third serial-parallel driver is connected with a pin 2d of the second phase shifter, and a pin 1e of the third serial-parallel driver is connected with a pin 2e of the second phase shifter.
As in the above embodiments, the connection between the second serial-parallel driver and the third phase shifter and the connection between the second serial-parallel driver and the fourth phase shifter may also be in the form of multiple wire connections, which are not described herein again.
In the prior art, the circuit structures of the phase shift functional modules of the four-channel multifunctional chip RFin-RFout1 channel, RFin-RFout2 channel, RFin-RFout3 channel, and RFin-RFout4 channel are prone to cause voltage standing wave ratio differences of four output ports of the four-channel multifunctional chip, thereby affecting the performance of the four-channel multifunctional chip, and the following description will take the circuit schematic diagram of the phase shift functional module in the prior art as an example.
FIG. 3 is a circuit diagram of a phase shift functional module of a four-channel multifunctional chip RFin-RFout1 channel in the prior art, which is composed of inductors Ind 1-Ind 7, capacitors C1-C6, resistors R1-R2 and PHEMT devices D1-D16. The IN port is connected to the first output terminal 2 of the 1-4 power divider IN the four-channel multifunctional chip, and the OUT port is the first output terminal RFout1 of the four-channel multifunctional chip. The capacitor C3-C5, the inductor Ind 5-Ind 7 and the PHEMT device D13-D16 form 180 degrees, the PHEMT device D12 is 5.625 degrees, the resistor R2, the inductor Ind4 and the PHEMT device D9-D11 form 22.5 degrees, the inductor Ind3 and the PHEMT device D8 form 11.25 degrees, the resistor R1, the inductor Ind2 and the PHEMT device D5-D7 form 45 degrees, the capacitor C1-C2, the inductor Ind1 and the PHEMT device D1-D4 form 90 degrees, and the specific power-up operation mode is shown in Table 1.
TABLE 1 PHEMT device grid voltage and phase shifter basic state comparison table
| |
Reference state
|
5.625°
|
11.25°
|
22.5°
|
45°
|
90°
|
180°
|
354.375°
|
| D1 |
0V
|
0V
|
0V
|
0V
|
0V
|
-5V
|
0V
|
-5V
|
| D2 |
0V
|
0V
|
0V
|
0V
|
0V
|
-5V
|
0V
|
-5V
|
| D3 |
-5V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
| D4 |
-5V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
| D5 |
0V
|
0V
|
0V
|
0V
|
-5V
|
0V
|
0V
|
-5V
|
| D6 |
-5V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
| D7 |
-5V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
| D8 |
0V
|
0V
|
-5V
|
0V
|
0V
|
0V
|
0V
|
-5V
|
| D9 |
0V
|
0V
|
0V
|
-5V
|
0V
|
0V
|
0V
|
-5V
|
| D10 |
-5V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
| D11 |
-5V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
| D12 |
0V
|
-5V
|
0V
|
0V
|
0V
|
0V
|
0V
|
-5V
|
| D13 |
-5V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
| D14 |
-5V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
| D15 |
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
-5V
|
-5V
|
| D16 |
0V
|
0V
|
0V
|
0V
|
0V
|
0V
|
-5V
|
-5V |
Fig. 4 is a circuit layout of a phase shift functional module of the channels of the four-channel multifunctional chip RFin-RFout1 in the prior art, and a capacitor C6 with a capacitance value of 0.58pF is arranged in a black frame. FIG. 5 is a diagram showing a test curve of voltage standing wave ratio of the first output port RFout1 of the four-channel multifunctional chip in the prior art, wherein the total number of the reference state and the phase-shifted state is 2 due to the 6-bit phase shifter with 5.625 degree step as the phase-shifting functional unit664 states, there are 64 voltage standing wave ratio curves. It can be seen from fig. 5 that the maximum value of all the voltage standing wave ratio curves reaches 2.6. FIG. 6 is a Smith chart test curve of RFout1 port impedance of the four-channel multifunctional chip under 64 states, the real part impedance of the circle center of the Smith chart is 50 Ω, and the corresponding voltage standing wave ratio is the best principleThe desired value is 1. Fig. 6 is a schematic diagram of a smith chart testing curve of impedance of the first output port RFout1 of the four-channel multifunctional chip in the prior art, and it can be seen from fig. 6 that a point farthest from the center of the smith chart is a point m1, and its partial impedance is 0.431 × 50 ═ 21.55 Ω, so that the voltage standing wave ratio at this point is the worst.
To the problem of the voltage standing wave ratio difference of four output ports of the multi-functional chip of four passageways among the prior art, this application provides an improved phase shift functional module, and wherein, improved phase shift functional module includes: the input end of the phase-shifting functional module, the phase-shifting circuit, the input end of the phase-shifting functional module and the output end of the phase-shifting functional module are sequentially connected. Wherein, decay circuit includes: and a pi-type fixed attenuator. The phase shift functional module is provided with the pi-shaped fixed attenuator, so that the voltage standing wave ratio of the output port of the multifunctional chip can be effectively improved.
Fig. 7 is a circuit diagram of an improved phase shift functional module according to an embodiment of the present invention.
As shown in fig. 7, the circuit of an improved phase shift functional module of this embodiment includes:
a third resistor R3, a fourth resistor R4, a fifth resistor R5, and a first ground GND 1; a first end of the third resistor R3 is connected to a first end of the fifth resistor R5, a second end of the fifth resistor R5 is connected to a first ground terminal, the first ground terminal is further connected to a first end of the fourth resistor R4, and a second end of the fourth resistor R4 is connected to a second end of the third resistor R3;
a first resistor R, a second resistor R, a first capacitor C, a second capacitor C, a third capacitor C, a fourth capacitor C, a fifth capacitor C, a first inductor Ind, a second inductor Ind, a third inductor Ind, a fourth inductor Ind, a fifth inductor Ind, a sixth inductor Ind, a seventh inductor Ind, a first PHEMT D, a second PHEMT D, a third PHEMT D, a fourth PHEMT D, a fifth PHEMT D, a sixth PHEMT D, a seventh PHEMT D, an eighth PHEMT D, a ninth PHEMT D, a tenth PHEMT D, an eleventh PHEMT D, a twelfth PHEMT D, a thirteenth PHEMT D, a fourteenth PHEMT D, a fifteenth PHEMT D, a sixteenth PHEMT D, a second ground terminal, a third ground terminal, a fourth GND terminal, a fifth ground terminal, a sixth ground terminal, and a seventh ground terminal GND;
a first end S of a fourteenth PHEMT D14 is connected to a first end of a fourth capacitor C4, a second end of a fourth capacitor C4 is connected to a first end of a seventh inductor Ind7 and a first end of a third capacitor C3, respectively, a second end of a seventh inductor Ind7 is connected to a second ground GND2, a second end of a third capacitor C3 is connected to a first end S of a thirteenth PHEMT D13, a second end D of a thirteenth PHEMT D13 is connected to a first end D of a twelfth PHEMT D12 and a first end D of a fifteenth PHEMT D15, a second end S of a fifteenth PHEMT D15 is connected to a first end of a fifth inductor Ind5, a second end of a fifth inductor Ind5 is connected to a first end of a sixth inductor Ind6 and a first end of a fifth capacitor, a second end of the fifth capacitor is connected to the third ground, a second end of the sixth inductor Ind6 is connected to a second end S16, and a second end of the fourteenth PHEMT 14 is connected to a second end S16;
a second end S of a twelfth PHEMT D12 is connected to a first end D of a ninth PHEMT D9, a third end M of the ninth PHEMT D9 is connected to a first end D of a tenth PHEMT D10 and a first end of a second resistor R2, respectively, a second end S of a tenth PHEMT D10 is connected to a first end S of an eleventh PHEMT D11 and a second end of a second resistor R2, respectively, a second end of the second resistor R2 is further connected to a first end of a fourth inductor Ind4, and a second end of the fourth inductor Ind4 and a second end D of the eleventh PHEMT D11 are both connected to a fourth ground terminal GND 4;
a second terminal S of the ninth PHEMT D9 is connected to the first terminal D of the eighth PHEMT D8, a third terminal M of the eighth PHEMT D8 is connected to the first terminal of the third inductor Ind3, and a second terminal of the third inductor Ind3 is connected to the fifth ground GND 5;
a second end S of the eighth PHEMT D8 is connected to a first end D of a fifth PHEMT D5, a third end M of the fifth PHEMT D5 is connected to a first end D of a sixth PHEMT D6 and a first end of a first resistor R1, respectively, a second end S of the sixth PHEMT D6 is connected to a first end S of a seventh PHEMT D7 and a second end of a first resistor R1, respectively, the second end of the first resistor R1 is further connected to a first end of a second inductor Ind2, and the second end D of the seventh PHEMT D7 and the second end of the second inductor Ind2 are both connected to a sixth ground terminal GND 6;
a second end S of a fifth PHEMT D5 is connected to a first end D of a second PHEMT D2, a second end S of a second PHEMT D2 is connected to a first end of a second capacitor C2, a second end of the second capacitor C2 is connected to a first end of a first capacitor C1 and a first end of a first inductor Ind1, respectively, a second end of the first inductor Ind1 is connected to a seventh ground GND7, a second end of the first capacitor C1 is connected to a first end S of the first PHEMT D1, a second end D of the first PHEMT D1 is connected to a first end D of a third PHEMT D3, a second end S of the third PHEMT D3 is connected to a first end S of a fourth PHEMT D4, and a second end D of the fourth PHEMT D4 is connected to a first end D of the second PHEMT D2;
the input terminal IN of the phase shift functional module is connected to the second terminal D of the first PHEMT D1, the second terminal D of the fourteenth PHEMT D14 is connected to the second terminal of the third resistor R3, and the first terminal of the third resistor R3 is connected to the output terminal OUT of the phase shift functional module.
As can be seen from fig. 7, in order to improve the voltage standing wave ratio of the RFout1 port, the capacitor C6 in fig. 3 is replaced by a pi-type fixed attenuator composed of R3 to R5 in fig. 7, where R3 is 10 Ω, R4 is 2900 Ω, and R5 is 2460 Ω. Fig. 8 is a circuit layout of the improved multi-function chip RFin-RFout1 channel phase shift functional module, and comparing fig. 4 and fig. 8, it can be seen that the layout in the black frame is replaced by a pi-type fixed attenuator formed by a capacitor C6 and resistors R3-R5.
FIG. 9 is a test curve of the voltage standing wave ratio of the port of the improved multifunctional chip RFout1 in 64 states, wherein the maximum value of the voltage standing wave ratio is 1.8; fig. 10 is a smith chart test curve of the RFout1 port impedance of the improved multifunction chip in 64 states, and it can be seen that the real impedance at point m1, which is farthest from the center of the smith chart, in all the curves is 0.726 × 50 — 36.3 Ω, which is closer to the center of the smith chart than 21.55 Ω before the improvement.
The phase shift functional units in the RFin-RFout2, RFin-RFout3 and RFin-RFout4 channels are the same as the phase shift functional units in the RFin-RFout1 channels, and the voltage standing wave ratios of the RFout2, RFout3 and RFout4 ports can be improved in the same way.
As can be seen by comparing fig. 5, 6, 9 and 10, the port voltage standing wave ratio can be effectively improved by replacing the capacitor with the pi-type fixed attenuator formed by the resistor and changing the port real part impedance of the circuit.
IN an embodiment, referring to fig. 2, an input terminal IN of the phase shift functional module is connected to an output port of the 1-to-4 power divider of the multifunctional chip, and an output terminal OUT of the phase shift functional module is an output port of the multifunctional chip.
Specifically, IN the case where the phase shift functional module is disposed IN the first phase shifter, the input terminal IN of the phase shift functional module is connected to the first output port 2 of the 1-to-4 power divider of the multifunctional chip, and the output terminal OUT of the phase shift functional module is the first output port RFout1 of the multifunctional chip. For the second phase shifter, the third phase shifter and the fourth phase shifter, the phase shift functional module is arranged, and the connection relationship between the input end IN of the phase shift functional module and the output end OUT of the phase shift functional module is the same as the principle, which is not described herein again.
The above examples are only intended to illustrate the technical solution of the present invention, but not to limit it; although the present invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical solutions described in the foregoing embodiments may still be modified, or some technical features may be equivalently replaced; such modifications and substitutions do not substantially depart from the spirit and scope of the embodiments of the present invention, and are intended to be included within the scope of the present invention.