CN212875746U

CN212875746U - Ku-band satellite communication power amplifier linearizer

Info

Publication number: CN212875746U
Application number: CN202021316635.XU
Authority: CN
Inventors: 蔡钟斌
Original assignee: Sichuan Zhongjiu Defense Technology Co ltd
Current assignee: Sichuan Zhongjiu Defense Technology Co ltd
Priority date: 2020-07-07
Filing date: 2020-07-07
Publication date: 2021-04-02
Anticipated expiration: 2030-07-07

Abstract

The utility model discloses a Ku wave band satellite communication power amplifier linearizer relates to the wireless communication power amplifier field, including the blocking electric capacity C1 that connects gradually, blocking electric capacity C2, varactor D1, varactor D2, blocking electric capacity C3 and blocking electric capacity C4, still including Schottky diode D3 and Schottky diode D4, one end of Schottky diode D3 is connected between blocking electric capacity C1 and blocking electric capacity C2, between one end blocking electric capacity C3 and the blocking electric capacity C4 of Schottky diode D4, the other end of Schottky diode D3 and Schottky diode D4 is all grounded; the input end of the variable capacitance diode D1 and the output end of the variable capacitance diode D2 are grounded at radio frequency through a bias high-resistance line. The utility model discloses simple structure, the practicality is strong, through changing offset voltage, can change range expansion and phase compression volume.

Description

Ku-band satellite communication power amplifier linearizer

Technical Field

The utility model relates to a wireless communication power amplifier field, especially a linear spinning disk atomiser of Ku wave band satellite communication power amplifier.

Background

In recent years, wireless communication has been rapidly developed, and mobile communication is moving from the fourth generation to the fifth generation, and various large communication operators around the world are getting close to a new generation of mobile communication stations around the world. With the rapid development of wireless mobile communication, radio frequency power amplifiers are widely applied in the fields of personal mobile phone communication, household broadcast television, aerospace, GPS positioning, military use and the like. The semiconductor device is used as a core device of a radio frequency power amplifier, and cannot achieve ideal effects in application due to inherent nonlinear characteristics of the semiconductor device. When the radio frequency power amplifier works in a linear region, the power amplifier output signal amplified by the power amplifier and the original power amplifier input signal are in a linear multiple relation, and other components and nonlinear distortion are not generated. However, at this time, the input signal power is low, the output power of the power amplifier is also low, the efficiency of the radio frequency power amplifier is low, and the power consumption and efficiency of the system, which are important indexes of the communication system, often cannot meet the requirements of the wireless communication system. If the efficiency requirement of the radio frequency power amplifier of the wireless communication system is considered, the power amplifier needs to work in a saturation region, but when the power amplifier works in the saturation region, larger amplitude and phase nonlinear distortion can be generated, so that the receiver can not restore the original transmission signal, and the transmission of the whole wireless communication system fails.

In order to solve the contradiction between the linearity and efficiency of the radio frequency power amplifier in the wireless communication system, the power amplifier also has higher linearity when working in a high-efficiency saturation region, thereby ensuring the transmission quality of the whole wireless communication system, and the research on the linearization technology of the radio frequency power amplifier is particularly important.

Theoretically, there are three methods to improve the linearity of a power amplifier: firstly, a super-linear device meeting the system performance requirement is selected. But this requires the selection of appropriate semiconductor materials and improved amplifier manufacturing processes. The method has huge cost and high technical difficulty, and has not been broken through for years. The second approach is to operate the amplifier in the linear region, but doing so greatly reduces power utilization. In this case, the power consumption of the amplifier is largely converted into heat energy, and the heat dissipation of the device is also a relatively large problem. Moreover, the high-power device is expensive, which results in high cost of the whole device. The third method is to adopt a linearization technique, that is, to adopt a proper peripheral circuit or a pre-algorithm to correct the nonlinear characteristic of the amplifier, so that the whole transmission channel can exhibit the effect of linearly amplifying the input signal.

The linearization technique mainly comprises negative feedback technique, power back-off technique, feedforward technique, LINC, envelope elimination and restoration and predistortion technique. The predistortion technology becomes the mainstream of the current research due to the characteristics of stable performance, simple structure, high adjustability, strong self-adaption and the like, and the predistortion technology and the power back-off technology are combined for use, so that better linearity can be obtained.

The general pre-distortion linearizer, which may be called "linearizer" for short, can only linearize one of a solid-state power amplifier or a traveling-wave tube amplifier, regardless of a single-path transmission type, a reflection type or a double-branch loop type structure, and the general linearizer has poor applicability. For solving the technical defect that exists in the present design, designed the utility model discloses.

Disclosure of Invention

The utility model aims to provide a: a Ku-band satellite communication power amplifier linearizer is provided to solve the problems in the background art.

The utility model adopts the technical scheme as follows:

the utility model relates to a Ku wave band satellite communication power amplifier linearizer, including blocking electric capacity C1, blocking electric capacity C2 that connect gradually, varactor D1, varactor D2, blocking electric capacity C3 and blocking electric capacity C4, still including Schottky diode D3 and Schottky diode D4, one end of Schottky diode D3 is connected between blocking electric capacity C1 and blocking electric capacity C2, between one end blocking electric capacity C3 and blocking electric capacity C4 of Schottky diode D4, and Schottky diode D3 and Schottky diode D4's the other end is all grounded; the input end of the variable capacitance diode D1 and the output end of the variable capacitance diode D2 are grounded at radio frequency through a bias high-resistance line.

Furthermore, the direct current bias circuit further comprises 3 direct current bias circuits, one ends of the 3 direct current bias circuits are respectively connected between the blocking capacitor C1 and the blocking capacitor C2, between the variable capacitance diode D1 and the variable capacitance diode D2 and between the blocking capacitor C3 and the blocking capacitor C4 in parallel, and the other ends of the 3 direct current bias circuits are respectively connected with Vcc1, Vcc2 and Vcc 3.

Furthermore, the direct current bias circuit is a three-port network, a transmission line with characteristic impedance of 50 omega is adopted between an input port and an output port of the direct current bias circuit, and a direct current port consists of a quarter-wavelength line and two quarter-wavelength fan-shaped pieces.

Further, the schottky diode D3 and the schottky diode D4 are formed in a leadless and non-packaging structure.

Further, the radio frequency input end of the dc blocking capacitor C1 and the radio frequency output end of the dc blocking capacitor C4 are both connected to a 50 Ω microstrip line.

To sum up, owing to adopted above-mentioned technical scheme, the beneficial effects of the utility model are that:

1. the utility model relates to a Ku wave band satellite communication power amplifier linearizer, which adopts a coupling blocking circuit, a direct current bias circuit and other connecting structures are integrated on a radio frequency PCB by adopting a microstrip line structure, and a soft substrate which has lower dielectric constant and lower loss at a millimeter wave frequency band is used; the Schottky diode and the variable capacitance diode are integrated on the radio frequency PCB in a welding mode, and finally the PCB is integrally sintered on the cavity and grounded. The design structure is simple, the cost is low, and the realization is easy.

2. The utility model relates to a ware is linearized to Ku wave band satellite communication power amplifier replaces the microstrip line between blocking electric capacity C3 and the blocking electric capacity C4 through the phase shifter that a pair of varactor constitutes, changes varactor's appearance value, can change the phase shift volume that moves the looks ware to obtain different phase characteristics, make phase characteristics independent control, can independently adjust amplitude distortion and phase distortion.

3. The utility model relates to a ware is linearized to Ku wave band satellite communication power amplifier adopts the middle mode that adds varactor of two-stage cascade, very big improvement the utility model discloses an adjustability, self-adaptation is strong.

4. The utility model relates to a Ku wave band satellite communication power amplifier linearizer, thereby the nonlinear curve that produces through the parallelly connected schottky diode of two-stage carries out the vector synthesis and obtains the nonlinear curve of final range expansion and phase compression/expansion, fits with the nonlinear curve of external power amplifier system, finally improves power amplifier's nonlinearity, improves communication quality, through changing bias voltage, can change range expansion and phase compression volume.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and that for those skilled in the art, other relevant drawings can be obtained according to the drawings without inventive effort, wherein:

fig. 1 is a block diagram of the present invention;

FIG. 2 is a graph of amplitude expansion obtained by varying VCC 1;

FIG. 3 is a graph of phase compression obtained by varying VCC 3;

FIG. 4 is an amplitude expansion/compression curve obtained by varying VCC 3;

fig. 5 is a graph of phase expansion/compression obtained by varying VCC 3.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the invention, i.e., the described embodiments are only some, but not all embodiments of the invention. The components of embodiments of the present invention, as generally described and illustrated in the figures herein, may be arranged and designed in a wide variety of different configurations. The features and properties of the present invention will be described in further detail with reference to the following examples.

Example one

As shown in fig. 1, the utility model relates to a Ku wave band satellite communication power amplifier linearizer, including blocking electric capacity C1, blocking electric capacity C2 that connect gradually, varactor D1, varactor D2, blocking electric capacity C3 and blocking electric capacity C4, still including schottky diode D3 and schottky diode D4, the one end of schottky diode D3 is connected between blocking electric capacity C1 and blocking electric capacity C2, between one end blocking electric capacity C3 and blocking electric capacity C4 of schottky diode D4, the other end of schottky diode D3 and schottky diode D4 is all grounded; the input end of the variable capacitance diode D1 and the output end of the variable capacitance diode D2 are grounded at radio frequency through a bias high-resistance line.

In a preferred embodiment of the present invention, the dc bias circuit further comprises 3 dc bias circuits, wherein one ends of the 3 dc bias circuits are respectively connected in parallel between the dc blocking capacitor C1 and the dc blocking capacitor C2, between the varactor diode D1 and the varactor diode D2, and between the dc blocking capacitor C3 and the dc blocking capacitor C4, and the other ends of the 3 dc bias circuits are respectively connected to Vcc1, Vcc2, and Vcc 3.

In a preferred embodiment of the present invention, the dc bias circuit is a three-port network, a transmission line with a characteristic impedance of 50 Ω is used between the input port and the output port, and the dc port is composed of a quarter-wavelength line and two quarter-wavelength segments.

In a preferred embodiment of the present invention, the schottky diode D3 and the schottky diode D4 are formed in a leadless and non-package structure.

In a preferred embodiment of the present invention, the radio frequency input end of the dc blocking capacitor C1 and the radio frequency output end of the dc blocking capacitor C4 are both connected to a 50 Ω microstrip line.

In the utility model, the radio frequency signal V0 enters from the radio frequency input port, enters the coupling blocking capacitor C1 through the input 50 omega microstrip line, and enters the main transmission line through the parallel coupling between the microstrip lines; the signal V0 generates a distorted radio frequency signal V1 with expanded amplitude and compressed phase through a Schottky diode D3 in parallel; the radio frequency signal V1 enters an adjustable phase shifter consisting of a variable capacitance diode D1 and a variable capacitance diode D2 through a blocking capacitor C2 with the same structure, the amplitude of the regenerated radio frequency signal V2, the amplitude of the signal V2 and the amplitude of the signal V1 are consistent without considering transmission loss, and the phase can be adjusted through the phase shifter; the radio frequency signal V2 enters the parallel Schottky diode D4 through the blocking capacitor C3 to generate a distorted radio frequency signal V3 with amplitude expansion and phase expansion/compression opposite to the nonlinear distortion phase of the power amplifier, and finally the distorted radio frequency signal V3 passes through the blocking capacitor C4 and is output through the output 50 omega microstrip line. The radio frequency input end is convenient to cascade with a power amplifier system by using a standard 50 omega microstrip line.

The Vcc1 and the Vcc3 respectively provide bias voltages for the Schottky diode D3 and the Schottky diode D4 through direct current bias circuits with the same structure, and nonlinear distortion curves with different amplitudes and phases can be obtained by changing the bias voltages; vcc2 provides bias voltage for varactor diode D1 and varactor diode D2 through DC bias circuit, changes phase shift amount of phase shifter by changing capacitance value of varactor diode D1 and varactor diode D2, so as to obtain different phase characteristics, input end of varactor diode D1 and output end of varactor diode D2 are grounded in radio frequency by way of bias high resistance line, so as to reduce influence on radio frequency signal on main transmission line; the schottky diode D3 and schottky diode D4 are grounded through a metallized via on the radio frequency PCB; the blocking capacitors C1 and C4 are devices which prevent direct current signals from entering the input/output end of the linearizer through the input/output microstrip line and affecting the front end or the back end of the linearizer; the dc blocking capacitors C2 and C3 prevent the bias voltages applied to the schottky diode D3 and schottky diode D4 from affecting the bias voltages of the varactor diode D1 and the varactor diode D2, and thus the overall output characteristics are not affected.

The utility model discloses a linearizer mainly used Ku wave band utilizes electronic design automation software ADS to carry out the circuit emulation to the linear circuit of predistortion. Based on the comprehensive consideration of factors such as cost, loss and the like, an RT/Duroid5880 soft substrate with a lower dielectric constant and extremely low loss is selected as a radio frequency PCB material for design, and the thickness of the PCB is selected to be 0.254mm which is commonly used. The utility model discloses a coupling dc blocking circuit, direct current bias circuit and other connection structure all adopt the integration of microstrip line structure on radio frequency PCB, and schottky diode D3, D4, varactor D1, D2 adopt the welded form integrated on radio frequency PCB, at last with the whole sintering of PCB ground connection on the cavity.

Blocking capacitors C1, C2, C3, C4: the schottky diode D3 and the schottky diode D4 are configured to operate in a nonlinear state, and a bias voltage is applied to change the operating state of the schottky diode D3 and the schottky diode D4 to avoid the mutual influence between the rf signal and the dc signal. The utility model discloses utilize the coupling between the microstrip line to transmit radio frequency signal and cut off direct current signal simultaneously, the main parameter that influences its performance is the line width, interval and the line length of coupling microstrip line.

The blocking capacitor adopts a microstrip line parallel coupling mode, the limitation of microstrip processing precision and processing clearance is considered, the width of the line width of the coupling line is selected to be 0.1mm, the distance between the coupling lines is 0.1mm, and the length of the coupling line is 4.1 mm. By optimizing the simulation insertion loss to be less than 0.1dB and the characteristic impedance of the two-port microstrip line of the blocking capacitor to be 50 omega, the front-stage circuit and the rear-stage circuit can be matched.

A direct current bias circuit: the bias voltage is applied to the diode, but the radio frequency signal cannot be transmitted from the feed end, so that the insertion loss of the linearizer is increased, and the effect is simply equivalent to that of an inductor. The dc bias circuit is a three-port network. Between the input and output ports is a transmission line with a characteristic impedance of 50 ohms. The dc port consists of a quarter-wave line and two quarter-wave segments, the quarter-wave segments corresponding to a grounded capacitor.

DC bias circuit also adopts the microstrip line, the utility model discloses a distinguish each way power, divide DC power supply into Vcc1, Vcc2, Vcc3, can be collectively called DC power supply Vcc, the external DC power supply Vcc of DC bias circuit's input, through DC feed and through the fan-shaped piece that resistance partial pressure got into high resistance line and both sides, the length of two fan-shaped pieces is the quarter wavelength, be equivalent to a grounded capacitor, Vcc rethread high resistance line gives schottky diode D3, D4 carries out DC feed. The combination of the quarter-wavelength fan-shaped structure capacitor and the quarter high-resistance wire can form an open circuit for radio-frequency signals in a certain bandwidth, prevent alternating current leakage caused by insufficient input impedance when a radio-frequency end looks at a direct current source, and prevent a direct current bias circuit from influencing the impedance characteristics of all parts of a radio-frequency signal circuit. While the static bias of schottky diode D3 or schottky diode D4 can be adjusted by changing Vcc so that the linearizer can be in the desired state. The line width of the high-resistance line is 0.13mm and the length of the quarter-wavelength line is 4.3mm through simulation optimization; the radius of the fan-shaped capacitor is 3.4mm, and the angle of the fan surface is 60 degrees; the voltage dividing and current limiting resistor is a chip resistor packaged as 0603, and the resistance value is 50 omega (can be adjusted according to actual debugging); the dc bias is supplied through a feedthrough capacitor.

Schottky diodes D3, D4: to avoid parasitic effects and additional losses, a diode model MA 4E-2037 was chosen, a leadless, package-less structure was used, and the diode cutoff frequency was calculated from the parameters provided by the model diode:

therefore, the device can be completely used for millimeter wave bands, has a very wide frequency response range, can be used for the predistortion design of Ku wave bands, and even can be used for millimeter wave bands. The Schottky diodes D3 and D4 are directly assembled at two ends of a strip line of a microstrip line of the radio frequency PCB in a sintering mode, and different nonlinear working states are obtained by adjusting bias voltage, so that different nonlinear distortion curves are finally generated. The nonlinear curves generated by the two-stage parallel Schottky diodes are subjected to vector synthesis to obtain the final amplitude expansion and phase compression/expansion nonlinear curves, and the final amplitude expansion and phase compression/expansion nonlinear curves are fitted with the nonlinear curves of an external power amplifier system, so that the nonlinearity of the power amplifier is finally improved, and the communication quality is improved.

Fig. 2 and 3 are graphs of amplitude expansion and phase compression obtained by changing the bias voltages VCC1 and VCC3 of schottky diodes D3 and D4, respectively, when the operating frequency is 14GHz, and the amount of amplitude expansion and phase compression can be changed by changing the bias voltage.

The radio frequency grounding structure: the grounding wire realizes radio frequency grounding by an open line of 1/4 wavelength corresponding to the central frequency, the structure also comprises a bias high-resistance wire to realize the reflection of a coupling port and a through port, and finally, the grounding wire is a metal through hole to realize the grounding of a direct current signal.

Varactors D1, D2: a diode with the model of MA46H146 is selected, a variable capacitance diode of the model is integrated on a GaAs material, chip packaging is adopted, the high Q value (Q is more than 15K) and the low total capacitance CT is less than 0.06pF, and the high Q value and the low total capacitance CT are very suitable for designing a Ku waveband phase shifter. The utility model provides a move looks ware and constitute by varactor D1 and varactor D2 butt joint, thereby obtain different phases through adjusting bias voltage to realize the independent regulation of phase place nonlinear distortion curve.

When the operating frequency is 14GHz, fig. 4 and 5 are curves of amplitude expansion and phase compression obtained by changing the bias voltage VCC2 of the varactors D1 and D2, respectively, and by changing the bias voltage, the phase compression/expansion amount can be changed, and the influence on the amplitude expansion amount is not great, so that the curves can be used for improving the linearity of the traveling wave tube or the solid-state power amplifier.

The above description is only for the preferred embodiment of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can be covered within the protection scope of the present invention without the changes or substitutions conceived by the inventive work within the technical scope disclosed by the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope defined by the claims.

Claims

1. A Ku waveband satellite communication power amplifier linearizer is characterized in that: the Schottky diode comprises a blocking capacitor C1, a blocking capacitor C2, a variable capacitance diode D1, a variable capacitance diode D2, a blocking capacitor C3, a blocking capacitor C4, a Schottky diode D3 and a Schottky diode D4, wherein the blocking capacitor C1 and the blocking capacitor C2 are connected at one end of the Schottky diode D3, the blocking capacitor C3 and the blocking capacitor C4 are connected at one end of the Schottky diode D4, and the Schottky diode D3 and the Schottky diode D4 are grounded at the other end; the input end of the variable capacitance diode D1 and the output end of the variable capacitance diode D2 are grounded at radio frequency through a bias high-resistance line.

2. The Ku band satellite communication power amplifier linearizer as claimed in claim 1, wherein: the three-phase alternating current direct current bias circuit further comprises 3 direct current bias circuits, one ends of the 3 direct current bias circuits are connected between the blocking capacitor C1 and the blocking capacitor C2, between the variable capacitance diode D1 and the variable capacitance diode D2 and between the blocking capacitor C3 and the blocking capacitor C4 in parallel, and the other ends of the 3 direct current bias circuits are connected with Vcc1, Vcc2 and Vcc 3.

3. The Ku band satellite communication power amplifier linearizer as claimed in claim 2, wherein: the direct current bias circuit is a three-port network, a transmission line with characteristic impedance of 50 omega is adopted between an input port and an output port of the direct current bias circuit, and a direct current port consists of a quarter-wave line and two quarter-wave fan-shaped pieces.

4. The Ku band satellite communication power amplifier linearizer as claimed in claim 2, wherein: the schottky diode D3 and the schottky diode D4 are of leadless and non-packaging structures.

5. The Ku band satellite communication power amplifier linearizer as claimed in claim 2, wherein: the radio frequency input end of the blocking capacitor C1 and the radio frequency output end of the blocking capacitor C4 are both connected with a 50 omega microstrip line.