Radar signal simulator with linearly adjustable equivalent radiation power and control method

Abstract

The invention belongs to the field of radar signal simulators, and particularly relates to a radar signal simulator with linearly adjustable equivalent radiation power and a control method. The driving amplifier and the power amplifier both adopt GaN amplifiers, and the grid voltage is respectively adjusted to enable each amplifier to work in the class A; a voltage-controlled attenuator is arranged at the output end of the up-conversion unit to carry out electric control attenuation on the radio frequency signal; a high-precision D / A output voltage is configured in the digital integration module and is used for precisely controlling the attenuation amount of the voltage-controlled attenuator; and a coupler and a detector are arranged at the output end of the ultra-wideband power amplifier module. The transmitting power of the ultra-wideband power amplifier module is calculated according to the output voltage of the detector, the attenuation amount required by the voltage-controlled attenuator is calculated by combining the gain curve of the ultra-wideband power amplifier module, the attenuation curve of the feeder line along with the frequency and the gain curve of the ultra-wideband antenna along with the frequency, and finally the output voltage of the high-precision D / A is controlled according to the attenuation amount. Therefore, the linear adjustability of the equivalent radiation power is realized.

Description

Technical Field

[0001] This invention belongs to the field of radar signal simulators, and specifically relates to a radar signal simulator and control method with linearly adjustable equivalent radiated power. Background Technology

[0002] The equivalent radiated power (ERP) of the radar and radar signal simulator is:

[0003]

[0004] Both the feeder and the antenna are passive devices, and the feeder loss and antenna gain are not adjustable after the hardware is finalized.

[0005] Traditional radar and radar signal simulators use saturated amplification in their power amplifier modules, so their output power remains constant, and therefore the equivalent radiated power of the equipment also remains constant.

[0006] For an ultra-wideband radar signal simulator, if the equivalent radiated power is to be linearly adjustable, the following factors need to be considered:

[0007] 1) Power amplifier modules are generally designed with saturation amplification as the goal, and the power cannot fall back from the saturation state or does not have linearity when falling back;

[0008] 2) Feeder loss increases with frequency. Taking the GYTA750 RF cable as an example, its loss is related to frequency as follows: Where K1 and K2 are constants. A 1-meter-long feeder has a loss of approximately 0.25 dB at a frequency of 2 GHz and approximately 0.75 dB at 18 GHz.

[0009] 3) Antenna gain increases with frequency. Taking the antenna gain G1 at 2GHz as a reference, the antenna gain at frequency f is approximately... At a frequency of 18 GHz, the antenna gain increases by approximately 19 dB compared to a frequency of 2 GHz.

[0010] Based on the above analysis, the output power, feeder loss, and antenna gain of the power amplifier module are not linear, making it difficult to achieve linearly adjustable equivalent radiated power. For example, if an equivalent radiated power of 10kW (50dBm) is required across the entire 2GHz to 18GHz frequency band, with a linear adjustment step of 1dB and a maximum pullback of 30dB, the following must be considered: the output power of the power amplifier module varies with frequency, as well as the undersaturation region at different frequency points (approximately a 15dB variation range), feeder loss (approximately a 0.5dB variation range), and antenna gain (approximately a 19dB variation range). Therefore, a controllable modulation range of at least 50dB must be reserved in the adjustable range before the power amplifier module to ensure that the equivalent radiated power meets the requirements across the entire frequency band. Summary of the Invention

[0011] To address the shortcomings of existing technologies, this invention provides a radar signal simulator and control method with linearly adjustable equivalent radiated power (ERP), which can achieve linear adjustment of ERP.

[0012] The technical solution of this invention is: a radar signal simulator with linearly adjustable equivalent radiated power, comprising a host computer, a digital synthesis module, an ultra-wideband frequency synthesis module, an up-conversion unit, an ultra-wideband power amplifier module, a feeder, and an ultra-wideband antenna. The host computer and the digital synthesis module communicate via an optical fiber connection. The high-precision A / D input port of the digital synthesis module is connected to the detector output port of the ultra-wideband power amplifier module. The I / V conversion output port of the digital synthesis module is connected to the voltage-controlled attenuation input port of the up-conversion unit. The high-speed D / A output terminal of the digital synthesis module is connected to the intermediate frequency input terminal of the up-conversion unit. The invention is characterized in that: the output terminal of the voltage-controlled attenuator of the up-conversion unit is connected to the input terminal of the ultra-wideband power amplifier module. The output of the coupler of the ultra-wideband power amplifier module is connected to the ultra-wideband antenna via a feeder. The ultra-wideband power amplifier module includes a driver amplifier, a power amplifier, a coupler, a detector, and a power conversion unit. The driver amplifier, power amplifier, coupler, and detector are connected in sequence. The power conversion unit supplies power to the driver amplifier and the power amplifier. The transmit power of the ultra-wideband power amplifier module is calculated based on the output voltage of the detector at the output of the ultra-wideband power amplifier module. Combining the gain curve of the ultra-wideband power amplifier module, the attenuation curve of the feeder with frequency, and the gain curve of the ultra-wideband antenna with frequency, the required attenuation of the voltage-controlled attenuator is calculated. Finally, the output voltage of the high-precision D / A converter of the digital synthesis module is controlled according to the attenuation.

[0013] According to the radar signal simulator with linearly adjustable equivalent radiated power as described above, the feature is that the drive amplifier and power amplifier in the ultra-wideband power amplifier module are GaN amplifiers, and the gate voltage is raised respectively so that each amplifier operates in Class A.

[0014] This invention also discloses a control method for a radar signal simulator with linearly adjustable equivalent radiated power, characterized by the following steps:

[0015] Step 1: The driver amplifier and power amplifier adopt GaN power amplifier to raise the gate voltage;

[0016] Step 2: Calculate the feeder line loss ,in Let i be the frequency of frequency point i. and It is a constant;

[0017] Step 3: Test the gain curve of the ultra-wideband antenna as a function of frequency within its operating frequency range, and record the gain of the ultra-wideband antenna at frequency point i. And store it as an "antenna gain table";

[0018] Step 4: The digital integrated module acquires the detector voltage output from the detector of the ultra-wideband power amplifier module, and then... (The sentence is incomplete and requires more context to be fully translated.) With input power Correspondence ,in For the slope of the detector, For the sensitivity of the detector, The output voltage of the detector at its sensitivity, and the coupling degree of the coupler. The current output power of the ultra-wideband power amplifier module is calculated as follows:

[0019]

[0020] Step 5: The host computer transmits the target value of the equivalent radiated power at frequency i. After the command is sent to the digital integration module, the digital integration module calculates the feeder line loss based on frequency point i. Consult the "Antenna Gain Table" to read the gain. Calculate the target transmit power value ;

[0021]

[0022] in, The target value of the equivalent radiated power in the radar signal simulator;

[0023] Step Six: Adjust the equivalent radiated power to the target value of the radar signal simulator. The attenuation of the time-controlled attenuator is ;when Less than Increase the attenuation of the voltage-controlled attenuator when Greater than At this time, the attenuation of the voltage-controlled attenuator is reduced.

[0024] According to the control method of the radar signal simulator with linearly adjustable equivalent radiated power as described above, the characteristic is that: in step six, the attenuation ATT of the voltage-controlled attenuator varies with the control voltage. The value decreases as the value increases, and the fitted curve is... ,in The slope of the voltage-controlled attenuator. It is a frequency-dependent constant; the numerical control adjustment range of a high-precision D / A converter is...

[0025]

[0026] Where n is the number of bits in D / A, This is the reference voltage for the D / A converter.

[0027] According to the control method of the radar signal simulator with linearly adjustable equivalent radiated power as described above, the characteristic is that the gate voltage is set to -2V, so that the linear amplification region of each amplifier is not lower than 30dB and the undersaturation region is narrow.

[0028] According to the control method of a radar signal simulator with linearly adjustable equivalent radiated power as described above, the characteristic is that the range between the frequency points in the antenna gain table is between 50MHz and 200MHz.

[0029] According to the control method of a radar signal simulator with linearly adjustable equivalent radiated power as described above, the characteristic is that the frequency points in the antenna gain table are between 100MHz.

[0030] The beneficial effect of this invention is that the equivalent radiated power (ERP) of the radar signal simulator can be linearly adjusted in 1dB steps within the ultra-wideband range of 2GHz to 18GHz. Attached Figure Description

[0031] Figure 1 This is a block diagram illustrating the principle of a radar signal simulator with linearly adjustable equivalent radiated power according to the present invention. Detailed Implementation

[0032] The specific embodiments of the present invention will now be described in further detail with reference to the accompanying drawings.

[0033] like Figure 1 As shown, a radar signal simulator with linearly adjustable equivalent radiated power includes a host computer, a digital synthesis module, an ultra-wideband frequency synthesis module, an up-conversion unit, an ultra-wideband power amplifier module, a feeder, and an ultra-wideband antenna. The host computer and the digital synthesis module communicate via fiber optic connection. The high-precision A / D input port of the digital synthesis module is connected to the detector output port of the ultra-wideband power amplifier module. The I / V conversion output port of the digital synthesis module is connected to the voltage-controlled attenuation input port of the up-conversion unit. The high-speed D / A output of the digital synthesis module is connected to the intermediate frequency input port of the up-conversion unit. The voltage-controlled attenuator output of the up-conversion unit is connected to the input port of the ultra-wideband power amplifier module. The coupler output of the ultra-wideband power amplifier module is connected to the ultra-wideband antenna via the feeder.

[0034] like Figure 1As shown, the ultra-wideband power amplifier module includes a driver amplifier (DA), a power amplifier (PA), a coupler, a detector, and a power conversion unit. The driver amplifier (DA), power amplifier (PA), coupler, and detector are connected sequentially, and the power conversion unit supplies power to the driver amplifier (DA) and power amplifier (PA). Both the driver amplifier (DA) and power amplifier (PA) in the ultra-wideband power amplifier module are GaN amplifiers. The gate voltages are raised to ensure each amplifier operates in Class A, thus achieving adjustable output power. The transmit power of the ultra-wideband power amplifier module is calculated based on the output voltage of the detector at the output terminal. Combining the gain curve of the ultra-wideband power amplifier module, the attenuation curve of the feeder with frequency, and the gain curve of the ultra-wideband antenna with frequency, the required attenuation of the voltage-controlled attenuator is calculated. Finally, the output voltage of the 12-bit high-precision D / A converter of the digital synthesis module is controlled according to the attenuation, thereby achieving linear adjustment of the equivalent radiated power.

[0035] This invention also discloses a control method for a radar signal simulator with linearly adjustable equivalent radiated power, comprising the following steps:

[0036] Step 1: Both the driver amplifier and power amplifier of the ultra-wideband power amplifier module adopt GaN power amplifiers, raising the gate voltage to around -2V, so that each stage of the amplifier has a linear amplification region of not less than 30dB and a relatively narrow undersaturation region. When selecting GaN power amplifiers, a certain power margin is reserved so that the power amplifiers in this scheme all operate in the linear amplification region.

[0037] Step 2: Calculate the feeder line loss (in Let i be the frequency of frequency point i. and It is a constant related to the selected cable.

[0038] Step 3: Test the gain curve of the ultra-wideband antenna in the range of 2GHz to 18GHz in a microwave anechoic chamber, and record the gain of the ultra-wideband antenna at frequency i. And store it as an "antenna gain table". The frequency range between the frequency points can be selected from 50MHz to 200MHz, and 100MHz is selected in this embodiment.

[0039] Step 4: The digital integrated module acquires the detector voltage output from the detector of the ultra-wideband power amplifier module, and then... (The sentence is incomplete and requires more context to be fully translated.) With input power Correspondence (in For the slope of the detector, For the sensitivity of the detector, (This refers to the output voltage of the detector at its sensitivity), and the coupling degree of the coupler. The current output power of the ultra-wideband power amplifier module is calculated as follows:

[0040]

[0041] Step 5: The host computer transmits the target value of the equivalent radiated power at frequency i. After the command is sent to the digital integration module, the digital integration module calculates the feeder line loss based on frequency point i. Consult the "Antenna Gain Table" to read the gain. Calculate the target transmit power value of the ultra-wideband power amplifier module. .

[0042]

[0043] in, The target value of the equivalent radiated power in the radar signal simulator;

[0044] Step Six: Adjust the equivalent radiated power to the target value of the radar signal simulator. The attenuation of the time-controlled attenuator is .when Less than Increase the attenuation of the voltage-controlled attenuator when Greater than At this time, the attenuation of the voltage-controlled attenuator is reduced. By controlling the output voltage of the high-precision D / A converter, the attenuation of the voltage-controlled attenuator is controlled, ultimately achieving the goal of linearly adjusting the equivalent radiated power. The attenuation ATT of the voltage-controlled attenuator varies with the control voltage. The value decreases as the value increases, and the fitted curve is... ,in The slope of the voltage-controlled attenuator. Let be a frequency-dependent constant. Then the numerical control adjustment amount of a high-precision D / A converter is:

[0045]

[0046] Where n is the number of bits in D / A, This is the reference voltage for the D / A converter. The negative feedback loop used in this scheme can be calibrated by repeatedly sampling the detector voltage output from the ultra-wideband power amplifier module to meet the target accuracy of the equivalent radiated power.

[0047] This invention enables precise step control of equivalent radiated power. Using two cascaded voltage-controlled attenuators, the maximum attenuation can reach 50dB. With a 12-bit high-precision D / A converter in the digital synthesis module, the voltage-controlled attenuation step can reach approximately 0.061dB. Analyzing frequency steps from 2GHz to 18GHz in 100MHz increments, line loss increases by approximately 0.003dB for every 100MHz increase in frequency, while antenna gain increases logarithmically by 0.05dB to 0.42dB. The 0.061dB attenuation step of the voltage-controlled attenuator can compensate for nonlinear changes in the power amplifier module's gain, feeder line loss, and antenna gain, allowing the adjustable step of equivalent radiated power to reach or even exceed 1dB. The apparatus and method of this invention are suitable for radar signal simulators requiring step adjustment of transmit power or equivalent radiated power.

Claims

1. A control method for a radar signal simulator with linearly adjustable equivalent radiated power, characterized in that: Includes the following steps: Step 1: The driver amplifier and power amplifier adopt GaN power amplifier to raise the gate voltage; Step 2: Calculate the feeder line loss ,in Let i be the frequency of frequency point i. and It is a constant; Step 3: Test the gain curve of the ultra-wideband antenna as a function of frequency within its operating frequency range, and record the gain of the ultra-wideband antenna at frequency point i. And store it as an "antenna gain table"; Step 4: The digital integrated module acquires the detector voltage output from the detector of the ultra-wideband power amplifier module, and then... (The sentence is incomplete and requires more context to be fully translated.) With input power Correspondence ,in For the slope of the detector, For the sensitivity of the detector, The output voltage of the detector at its sensitivity, and the coupling degree of the coupler. The current output power of the ultra-wideband power amplifier module is calculated as follows: Step 5: The host computer transmits the target value of the equivalent radiated power at frequency i. After the command is sent to the digital integration module, the digital integration module calculates the feeder line loss based on frequency point i. Consult the "Antenna Gain Table" to read the gain. Calculate the target transmit power value ; in, The target value of the equivalent radiated power in the radar signal simulator; Step Six: Adjust the equivalent radiated power to the target value of the radar signal simulator. The attenuation of the time-controlled attenuator is ;when Less than Increase the attenuation of the voltage-controlled attenuator when Greater than At this time, the attenuation of the voltage-controlled attenuator is reduced.

2. The control method for a radar signal simulator with linearly adjustable equivalent radiated power according to claim 1, characterized in that: Step 6: The attenuation ATT of the voltage-controlled attenuator varies with the control voltage. The value decreases as the value increases, and the fitted curve is... ,in The slope of the voltage-controlled attenuator. It is a constant related to frequency; The numerical control adjustment range of high-precision D / A converters is Where n is the number of bits in D / A, This is the reference voltage for the D / A converter.

3. The control method for a radar signal simulator with linearly adjustable equivalent radiated power according to claim 1 or 2, characterized in that: The gate voltage is set to -2V, ensuring that each stage of the amplifier has a linear amplification range of no less than 30dB and a narrow undersaturation range.

4. The control method for a radar signal simulator with linearly adjustable equivalent radiated power according to claim 1 or 2, characterized in that: The frequency range in the "Antenna Gain Table" is between 50MHz and 200MHz.

5. The control method for a radar signal simulator with linearly adjustable equivalent radiated power according to claim 1 or 2, characterized in that: The frequency range in the "Antenna Gain Table" is between 100MHz.

6. A radar signal simulator with linearly adjustable equivalent radiated power, comprising a host computer, a digital synthesis module, an ultra-wideband frequency synthesis module, an up-conversion unit, an ultra-wideband power amplifier module, a feeder, and an ultra-wideband antenna. The host computer and the digital synthesis module communicate via an optical fiber connection. The high-precision A / D input port of the digital synthesis module is connected to the detector output port of the ultra-wideband power amplifier module. The I / V conversion output port of the digital synthesis module is connected to the voltage-controlled attenuation input port of the up-conversion unit. The high-speed D / A output terminal of the digital synthesis module is connected to the intermediate frequency input terminal of the up-conversion unit. The simulator is characterized in that: The output of the voltage-controlled attenuator of the upconversion unit is connected to the input of the ultra-wideband power amplifier module. The output of the coupler of the ultra-wideband power amplifier module is connected to the ultra-wideband antenna via a feeder. The ultra-wideband power amplifier module includes a driver amplifier, a power amplifier, a coupler, a detector, and a power conversion unit. The driver amplifier, power amplifier, coupler, and detector are connected in sequence. The power conversion unit supplies power to the driver amplifier and the power amplifier. The transmit power of the ultra-wideband power amplifier module is calculated based on the output voltage of the detector at the output of the ultra-wideband power amplifier module. Combining the gain curve of the ultra-wideband power amplifier module, the attenuation curve of the feeder with frequency, and the gain curve of the ultra-wideband antenna with frequency, the required attenuation of the voltage-controlled attenuator is calculated. Finally, the output voltage of the high-precision D / A converter of the digital synthesis module is controlled according to the attenuation.

7. A radar signal simulator with linearly adjustable equivalent radiated power according to claim 6, characterized in that: The driver amplifier and power amplifier in the ultra-wideband power amplifier module are GaN amplifiers, and the gate voltage is raised to make each amplifier operate in Class A.

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