A high-frequency front-end device and a testing method based on OIP3 testing

Abstract

The application provides a high-frequency front-end device and a testing method based on OIP3 testing, which is divided into high-output and low-output channels through two radio frequency sources, a manually adjustable attenuator is arranged in the high-output channel to control the output amplitude, isolators are arranged in the high-output and low-output channels to suppress leakage signals, the radio frequency signals of the two channels are combined into one signal output through a combiner, and meanwhile, the signal combined into one is also output through a coupler to output a coupling signal and an output signal, the coupling signal is used to monitor the amplitude of the output signal in real time, and the output signal is finally output through a process control attenuator to realize linear output modulation. The amplitude of the output signal can be flexibly adjusted, real-time monitoring is supported, various application scenarios are adapted, different power requirements are met, a high dynamic range is possessed, high-precision and stable linear modulation is supported, and reliability under a high-power signal is ensured.

Description

Technical Field

[0001] This invention relates to the field of high-frequency radio communication technology, and specifically to a high-frequency front-end device and testing method based on OIP3 testing. Background Technology

[0002] E-band (60GHz-90GHz), with its short wavelength and wide frequency band, is widely used in millimeter-wave applications, making it a promising candidate for applications in communications, radar, and remote sensing. The Output Third-Order Intercept Point (OIP3) performance of millimeter-wave systems is a key indicator for these applications. In signal transmission and reception, OIP3 and IM3 are two important parameters in RF circuit design and testing, especially for systems with high dynamic range. While low-frequency OIP3 and IM3 testing can directly utilize two independent signal sources, with the development of communications and the increase in frequency, ordinary signal sources cannot meet the frequency requirements. Furthermore, high-frequency interference, harmonic suppression, and signal amplitude balance are all critical factors affecting signal linearity, making accurate and systematic testing difficult. Summary of the Invention

[0003] To overcome the shortcomings of existing technologies, this invention proposes a high-frequency front-end device and testing method based on OIP3 testing. By combining a high-directivity combiner and an isolator, the signal crosstalk problem is solved, unnecessary intermodulation products are avoided, and the accuracy of test results is improved.

[0004] To achieve the above objectives, the present invention provides a high-frequency front-end device based on OIP3 testing, comprising a high-power channel 6th order frequency multiplier 1 with an output power of +17dBm; a high-power channel manually adjustable attenuator 3; a high-power channel E-band isolator 4; a low-power channel 6th order frequency multiplier 2 with an output power of +15dBm; a low-power channel E-band isolator 5; a combiner 6; an E-band coupler 7; and an E-band programmable attenuator 8, wherein:

[0005] The high-power channel input signal is sent to the manually adjustable attenuator 3 after passing through the 6th frequency multiplier 1, and then to the combiner 6IN1 port after passing through the E-band isolator 4.

[0006] The low-power channel input signal is fed to the 6IN2 port of the combiner after passing through the 6th frequency multiplier 2 and the E-band isolator 5;

[0007] Combiner 6 combines the two signals and outputs them to the E-band unidirectional coupler 7;

[0008] The E-band coupler 7 performs power monitoring and sends the output to the E-band programmable attenuator 8 via a direct pass-through. After attenuation, the output is then output, thereby achieving linear output modulation.

[0009] Furthermore, the input channels are two independent channels: a high-power channel and a low-power channel. Both the high-power channel and the low-power channel use a 6th-order frequency multiplier. The output power of the high-power output channel is +17dBm, and the output power of the low-power output channel is +15dBm. The output frequency range is 60GHz to 90GHz.

[0010] Furthermore, a manually adjustable attenuator is provided in the high-power output channel, with an attenuation range of 0dB to -30dB.

[0011] Furthermore, E-band isolators are installed in both the high-power output channel and the low-power output channel.

[0012] Furthermore, the E-band programmable attenuator is a high-linearity programmable attenuator with an attenuation range of 0dB to -35dB.

[0013] Furthermore, the specifications of the combiner are as follows:

[0014] Operating frequency: E-band 60GHz to 90GHz;

[0015] Intra-band insertion loss: ≤1dB;

[0016] Output port isolation: ≥30dB;

[0017] Input and output VSWR: ≤1.6.

[0018] Furthermore, the coupling value of the E-band unidirectional coupler is 10dB, and its specifications are as follows:

[0019] Operating frequency: E-band 60GHz to 90GHz;

[0020] Intra-interpolation loss: ≤1dB;

[0021] Coupling flatness: ≤1dB;

[0022] VSWR at input, output and coupling terminals: ≤1.20.

[0023] Furthermore, the specifications of the E-band isolator are as follows:

[0024] Operating frequency: E-band 60GHz to 90GHz;

[0025] Intra-interpolation loss: ≤1dB;

[0026] Reverse isolation: ≥25dB.

[0027] Furthermore, the E-band programmable attenuator is a high-linearity programmable attenuator with an attenuation range of 0dB to -35dB.

[0028] A testing method for a high-frequency front-end device based on OIP3 testing, applicable to any of the high-frequency front-end devices based on OIP3 testing described in this paper.

[0029] Step 1: Accurately calibrate the nonlinear characteristics, channel synchronization, and temperature effects of the system by injecting dual-tone signals, measuring time delays, and modeling temperature compensation.

[0030] Step 2: Employ dual-loop power control, time delay tracking, and intermodulation component extraction techniques to ensure signal stability, phase synchronization, and accurate intermodulation component analysis.

[0031] Step 3: Process multi-dimensional data using the three-slope method and weighted average to accurately calculate OIP3 and evaluate the reliability of the results.

[0032] Step 4: Design a multi-level overpower protection and phase-locked loop recapture process to ensure stable operation and automatic recovery of the system under abnormal conditions.

[0033] Furthermore, step 1 is detailed as follows:

[0034] Step 11: Input the baseband signal to both the high channel and the low channel simultaneously, and convert the baseband signal to the target frequency through a frequency multiplication process; then, increase or decrease the frequency offset on the baseband, ranging from 1MHz to 50MHz, to capture the nonlinear effects of the system.

[0035] Step 12: Collect five key frequency points at the output, including the two signals after frequency offset, the intermodulation component, and the center frequency. This data is used for subsequent nonlinear coefficient extraction. Based on the collected data, solve for the coefficient matrix reflecting the nonlinear relationship of the signals using the least squares method. These coefficients describe the nonlinear transfer characteristics between the input and output signals. The frequency calculation is as follows:

[0036] f1 = 6·(f base +Δf);

[0037] f2=6·(f base -Δf);

[0038] Among them, f base Baseband (10GHz);

[0039] Δf: Frequency offset, ranging from 1MHz to 50MHz (in 1MHz steps);

[0040] f1 and f2: The frequencies of the two-tone signal after frequency offset;

[0041] Intermodulation component calculation:

[0042] IM31 = 2·f1 - f2;

[0043] IM32 = 2·f2 - f1;

[0044] Among them, IM31 and IM32: intermodulation products, representing the distortion frequency generated by the nonlinear effect of the fundamental frequency signal;

[0045] Center frequency calculation:

[0046]

[0047] Among them, f c The center frequency is the average frequency of the two-tone signal and is used as the reference frequency for subsequent calculations.

[0048] Calculation of the nonlinear coefficient matrix H:

[0049] V out =H·V 3 in ;

[0050] Among them, V out : The amplitude vector of the output signal.

[0051] V 3 in : The cubic direction quantity of the input signal, used to capture the nonlinear characteristics of the signal.

[0052] H=[α,β,γ,δ] T The nonlinear coefficient matrix contains four coefficients, reflecting the nonlinear effects of the signal, and is solved using the least squares method.

[0053] Step 13: Inject a linear frequency modulated signal and use a cross-correlation algorithm to calculate the time delay difference between the high and low channels. The cross-correlation algorithm helps detect signal peaks, thereby determining the time delay difference. Based on the calculated time delay difference, generate a corresponding phase compensation table for each frequency point. The compensation table is used to adjust the system phase to correct signal distortion caused by the time delay difference.

[0054] The time delay difference is measured as follows:

[0055] Cross-correlation function:

[0056] R xy (τ)=∫x(t·y(t-τ)dt;

[0057] Among them, R xy (τ): Cross-correlation function, representing the similarity between two signals.

[0058] τ: Delay difference;

[0059] The time delay difference Δτ is determined by maximizing the cross-correlation function, with a resolution of 5 picoseconds.

[0060] Phase compensation table calculation:

[0061] Φ comp (f)=2πfΔτ+Φ offset (f);

[0062] Where, Φ comp (f): Phase compensation amount at frequency f.

[0063] Δτ: time delay difference

[0064] Φ offset (f): The static phase offset of the system obtained from the measured S-parameter data.

[0065] Step 14: Heat the frequency multiplier under different temperature conditions (25℃ to 85℃) and record the changes in output power. By recording the temperature changes, obtain the relationship between output power and temperature. Fit a compensation curve using the temperature change data. Based on this curve, the effect of temperature on power can be calculated, and the corresponding compensation coefficient can be obtained for subsequent temperature correction.

[0066] Temperature compensation formula:

[0067] ΔP = a(T - T0) 2 +b(T-T0)+c;

[0068] Where ΔP represents the change in output power.

[0069] T: Current temperature.

[0070] T0: Calibration temperature (typically 25℃)

[0071] a, b, c: Compensation coefficients obtained through experiments, fitting the effect of temperature on power.

[0072] Furthermore, step 2 is detailed as follows:

[0073] Step 21: A dual-loop control structure is adopted. The outer loop is responsible for coarse power adjustment, which adjusts the gain by comparing the actual power and the target power. The inner loop performs fine adjustment, which continuously adjusts the power of the auxiliary coupling end through the PID control algorithm to ensure that the system reaches a stable state.

[0074] Dual-loop control structure: Outer loop (coarse power adjustment) gain adjustment

[0075]

[0076] Among them, A manual: Manual gain adjustment amount; this formula is used to coarsely adjust the gain based on the power difference.

[0077] Inner loop (fine adjustment) gain adjustment

[0078] ΔA=0.8·e(t)+0.05·∫e(t)dt+0.2·(e(t)-e(t-1));

[0079] Where e(t) is the error function, representing the difference between the auxiliary coupling power and the target auxiliary power.

[0080] This formula uses a PID algorithm to achieve fine adjustment, where 0.8, 0.05, and 0.2 are the proportional, integral, and derivative coefficients, respectively.

[0081] Actual power compensation:

[0082]

[0083] Among them, P real Actual power after compensation

[0084] P meas Measured power

[0085] V high High channel voltage

[0086] V linear Linear operating point voltage.

[0087] Step 22: In order to compensate for the power distortion caused by nonlinear effects, the output power is adjusted in real time. The power is compensated by a correction factor to ensure that the measured power is close to the ideal value.

[0088] Latency dynamic tracking:

[0089] Δτ new =(t peak HP -t peak LP )×0.87;

[0090] Among them, t peak HP and t peak LP : These represent the peak times for the high channel and the low channel, respectively;

[0091] 0.87: Microstrip line velocity factor, taking into account the signal propagation speed in the microstrip line;

[0092] Phase compensation calculation:

[0093]

[0094] Where ΔΦ: phase difference compensation amount

[0095] f current Current frequency

[0096] Δτ new : Updated latency difference.

[0097] Step 23: Inject a pulse signal every 10ms and update the delay difference by detecting the peak time of the signal. Based on this updated information, accurately adjust the signal delay difference. After updating the delay difference, calculate the required phase compensation and adjust the phase of the system in real time to ensure the synchronization of the signal.

[0098] Step 24: Using a blind source separation algorithm, intermodulation components are extracted from the acquired signal. This process can separate intermodulation components generated by nonlinear effects from other noise components. After extracting the intermodulation components, an adaptive thresholding algorithm is used to remove the noise floor to obtain the true intermodulation component power, thereby calculating OIP3 more accurately.

[0099] Blind source separation algorithm:

[0100] Demixing matrix calculation:

[0101] Y = W·X;

[0102] Where X: observation matrix, containing intermodulation components and noise basis.

[0103] W: Unmixing matrix, calculated using the FastICA algorithm.

[0104] Y: Independent component, which is the intermodulation component extracted from the original signal;

[0105] Noise floor subtraction:

[0106] Calculation of the power of the intermodulation component after denoising:

[0107]

[0108] Among them, P IM3true Intermodulation component power after noise removal

[0109] P IM3meas : The measured power of the intermodulation component

[0110] P noise : Noise floor power.

[0111] Furthermore, step 3 is detailed below:

[0112] Step 31: At different power levels, the OIP3 is calculated using the three-slope method. OIP3 is estimated by the difference between the fundamental frequency power and the intermodulation component power, and is used to measure the linear range of the system. The OIP3 value is weighted and averaged using three different calculation methods: the two-tone equal amplitude method, the power extrapolation method, and the noise basis method, to obtain the final OIP3 value. Three-slope method calculation:

[0113] OIP3 calculation:

[0114]

[0115] Among them, P find : Fundamental frequency power

[0116] P IM3 Intermodulation component power

[0117] CF: Correction factor, taking into account bandwidth and device correction;

[0118] The combined results are weighted and the combined result of the three methods is taken:

[0119] Two-tone equal amplitude method: weight 0.6

[0120] Power extrapolation method: weight 0.3

[0121] Noise-based method: weight 0.1.

[0122] Step 32: Calculate the uncertainty of the measurement results, including measurement errors in power, phase, and temperature. By analyzing these error sources, obtain the total uncertainty. Total uncertainty calculation:

[0123]

[0124] Among them, u pwr u phase and u temp These represent the measurement uncertainties for power, phase, and temperature, respectively.

[0125] If the following conditions are met:

[0126] The standard deviation of the three measurements was <0.2 dB.

[0127] Intermodulation ratio (IMR) > 15 dB

[0128] Output the final OIP3 value; otherwise, trigger a retest.

[0129] Step 33: Determine the validity of the OIP3 calculation result by judging whether the standard deviation and cross-modulation ratio (IMR) of the three measurements meet the set criteria. If they do:

[0130] The standard deviation of the three measurements was <0.2 dB.

[0131] Intermodulation ratio (IMR) > 15 dB

[0132] If the final OIP3 value is not output, a retest will be triggered.

[0133] Furthermore, step 4 is detailed below:

[0134] Step 41: Design a multi-level overpower protection mechanism to take progressively responsive measures when output power exceeds the limit. For example, when the power exceeds 18dBm, the system will automatically introduce attenuation; if the over-limit continues, the low-level channel will be shut down; in extreme cases, the system will perform a hard cutoff.

[0135] The response mechanism is as follows:

[0136] Level 1 (P) out >18dBm): Programmable attenuator cut-in to -3dB

[0137] Level 2: Shut down the low channel if the limit is exceeded for 10ms.

[0138] Level 3: When the instantaneous over-limit exceeds +20dBm, the relay is hard-cut off.

[0139] Step 42: When phase lockout occurs in the system, the phase-locked loop (PLL) recapture process is initiated. Through steps such as reducing the bias voltage, injecting a reference signal, and scanning the tuning voltage, system stability is restored, ensuring the output signal is relocked and normal power output is restored. PLL recapture process steps:

[0140] 1. Reduce the frequency multiplier bias voltage to 50%.

[0141] 2. Inject reference signal -30dBm

[0142] 3. Scan VCO tuning voltage (10MHz step)

[0143] 4. Restore the lock and restore full power.

[0144] Compared with the prior art, the beneficial effects of the present invention are:

[0145] 1. This invention provides a high-frequency front-end device and testing method based on OIP3 testing. The high-frequency front-end device supports single-channel use as a frequency extension source, and also supports dual-channel simultaneous input of signals of the same frequency or arbitrary frequency difference within the bandwidth for combined output, exhibiting high flexibility and adjustability. It can effectively realize the testing of OIP3 and IM3 in the E-band (60GHz-90GHz), providing strong support for the evaluation of the linear characteristics of high-frequency signals.

[0146] 2. This invention provides a high-frequency front-end device and testing method based on OIP3 testing. It adopts 6th harmonic suppression frequency doubling technology, which can effectively suppress harmonic components, reduce nonlinear distortion, and make the output signal purer. By combining a high-directivity combiner and an isolator, the signal crosstalk problem is solved, unnecessary intermodulation products are avoided, and the accuracy of the test results is improved.

[0147] 3. This invention provides a high-frequency front-end device and testing method based on OIP3 testing, which can accurately test OIP3 and IM3 in the E-band, optimizes the performance of the high-frequency front-end device, is suitable for high-precision signal analysis, and effectively reduces signal crosstalk and nonlinear distortion by combining 6th frequency doubling technology and high directional isolation design, thus ensuring the accuracy and reliability of the measurement results.

[0148] 4. This invention provides a high-frequency front-end device and testing method based on OIP3 testing. The method enables real-time monitoring and adjustment, allowing flexible control of output power and frequency, ensuring stable operation of the system within a high dynamic range, supporting linear modulation and frequency extension of high-frequency signals, and adapting to testing requirements of different bandwidths and frequencies through appropriate adjustment methods. Attached Figure Description

[0149] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0150] Figure 1 This is a circuit diagram of the present invention;

[0151] Figure 2 This is a schematic diagram of the OIP3 and IM3 test connection of the present invention;

[0152] Figure 3 The OIP3 characteristic of this invention;

[0153] Figure 4 This is the output power curve of the present invention;

[0154] Figure 5 This is a diagram illustrating the steps of the method of the present invention.

[0155] Figure 1 The components include: a high-power channel 6th frequency multiplier (1); a high-power channel manually adjustable attenuator (3); a high-power channel E-band isolator (4); a low-power channel 6th frequency multiplier (2); a low-power channel E-band isolator (5); a combiner (6); an E-band coupler (7); and an E-band programmable attenuator (8). Detailed Implementation

[0156] The technical solution of the present invention will be more clearly and completely explained below with reference to the accompanying drawings and through the description of preferred embodiments of the present invention.

[0157] like Figure 1 As shown, in this embodiment of the invention, a high-frequency front-end device based on OIP3 testing includes a high-power channel 6th frequency multiplier 1; a high-power channel manually adjustable attenuator 3; a high-power channel E-band isolator 4; a low-power channel 6th frequency multiplier 2; a low-power channel E-band isolator 5; a combiner 6; an E-band coupler 7; and an E-band programmable attenuator 8. The high-power channel input signal, after being multiplied by the 6th frequency multiplier 1, is sent to the manually adjustable attenuator 3, then to the combiner 6IN1 port via the E-band isolator 4; the low-power channel input signal, after being multiplied by the 6th frequency multiplier 2, is sent to the combiner 6IN2 port via the E-band isolator 5. The combiner 6 combines the two signals and outputs the combined signal to the E-band coupler 7. The E-band coupler 7 couples the output for power monitoring, and the direct output is output after programmable attenuation, achieving linear output modulation.

[0158] To achieve linear output power and perform high-frequency OIP3 measurement, two low-frequency signal sources (upper limit 15GHz) are used as input signals to the high and low output channels, respectively, generating two continuous wave (CW) signals at different frequencies. The two low-frequency signal sources are synchronized with a reference clock to ensure phase consistency. The high and low output signals are combined into a single signal and sent to a spectrum analyzer. A manual attenuator on the high output channel is used to adjust the high and low output signals to achieve amplitude parity. The combined power passes through a unidirectional coupler, and the coupled path is sent to a power meter to monitor the combined power value. The direct path signal is then attenuated stepwise by a programmable attenuator to linearly adjust the final output power, inputting appropriate power to the device under test (DUT). Real-time monitoring of the device's output power ensures linear output. Finally, the spectrum analyzer acquires and analyzes the output signal of the DUT. The fundamental frequency and third-order intermodulation product (IM3) in the signal are analyzed, and OIP3 is calculated. OIP3 = Pout + ΔP / 2, where Pout is the fundamental power and ΔP is the difference between the fundamental power and the third-order intermodulation product power.

[0159] Please see Figure 1 In this embodiment of the invention, at the input end of the device, low-frequency signal source 1 and low-frequency signal source 2 respectively input frequency and power to the high and low output channels, with low-frequency signal sources 1 and 2 having a synchronous clock reference. The two signals are combined into one signal output by this device, and at the combined output end, one signal is coupled to a power meter to monitor the power value by a unidirectional coupler. Finally, the power output is controlled by a programmable attenuator.

[0160] Please see Figure 2In this embodiment of the invention, the output terminal of the device, the test connection diagram of OIP3 and IM3, the coupling port is connected to the power meter for real-time power monitoring, and the output port is connected to the spectrum analyzer for signal analysis.

[0161] Please see Figure 3 In this embodiment of the invention, the high-power channel input frequency f1 = 76 GHz, the low-power channel input frequency = 76.1 GHz, f1-f2 = 100 MHz are used, and the output amplitude balance is adjusted by manually adjustable attenuation, with the OIP3 characteristic at an output power of +15 dBm.

[0162] Please see Figure 4 In this embodiment of the invention, the output power curves of the high-power and low-power channels were tested respectively.

[0163] The working principle of this invention is as follows: The high-frequency front-end device based on OIP3 testing supports single-channel use as a frequency extension source; it can also simultaneously input signals of the same frequency or any frequency difference within the bandwidth into dual channels and combine them for output. A manually adjustable attenuator is set on the high-power channel to adjust the output amplitude balance. A power meter is connected to the coupling port of the coupler to monitor the output power in real time. The output port is equipped with a highly linear dynamic programmable attenuation to achieve linear output modulation. Currently, there are very few devices for OIP3 testing at the high-frequency module level, and the systems are scattered, requiring repeated calibration and power adjustments, making the testing process complex. The device of this invention is highly integrated, allowing for flexible switching between single and dual channels, precise balancing, real-time monitoring of output power, and automated output control. This significantly improves testing efficiency and meets the needs of high-frequency applications.

[0164] As one specific implementation, a high-frequency front-end device based on OIP3 testing utilizes two low-frequency (upper limit 15GHz) signal sources. These sources are divided into high and low output channels via two RF sources. A single channel can be used as a frequency extension source; alternatively, both channels can simultaneously input signals of the same frequency or any frequency difference within the bandwidth and combine them for output. The high output channel is equipped with a manually adjustable attenuator to control the output amplitude. Both high and low output channels are equipped with isolators to suppress leakage signals. The two RF output signals are combined into a single output signal via a combiner. Simultaneously, the combined signal is coupled to output a coupling signal and an output signal via a coupler. The coupling signal is sent to a power meter to monitor the magnitude and amplitude of the output signal in real time. Finally, the output signal is processed by a process-controlled attenuator to achieve linear output modulation.

[0165] In the high-frequency front-end device based on OIP3 testing, the high-output channel uses a 6th frequency multiplier with an input drive power of +5dBm and an input frequency of 10GHz-15GHz; the output frequency is 60GHz-90GHz, the output power is +17dBm, the 5th harmonic is suppressed to -40dBc, and the 7th harmonic is suppressed to -30dBc.

[0166] In the high-frequency front-end device based on OIP3 testing, the low-output pass also uses a 6th harmonic multiplier, with an input drive power of +5dBm and an input frequency of 10GHz-15GHz; the output frequency is 60GHz-90GHz, the output power is +15dBm, and the 5th harmonic is suppressed to -30dBc, and the 7th harmonic is suppressed to -30dBc.

[0167] In a high-frequency front-end device based on OIP3 testing, when using a single channel, both the high and low output channels can be used independently as a frequency extension source. The output power of the high output channel can be changed by a manually adjustable attenuator (located in the high output channel), with the output power range between -13dBm and +17dBm.

[0168] In high-frequency front-end devices based on OIP3 testing, when dual channels with different frequencies are used simultaneously, a manually adjustable attenuator is set in the high output channel. The amplitude can be finely adjusted in the spectrum to balance the power amplitude with that of the low output channel, thereby achieving amplitude leveling at different frequencies.

[0169] In the high-frequency front-end device based on OIP3 testing, two low-frequency (upper limit 15GHz) signal sources are synchronized with a clock reference to drive the high and low channels, ensuring signal phase consistency.

[0170] In the high-frequency front-end device based on OIP3 testing, the combiner is an E-band high-directivity combiner, used in conjunction with an isolator to improve signal crosstalk suppression. The combiner has a two-port isolation of 30dB, a port VSWR ≤1.6, and an insertion loss ≤1dB. The isolator has a reverse isolation ≥25dB ​​and an insertion loss ≤1.5dB.

[0171] In the high-frequency front-end device based on OIP3 testing, the coupler is an E-band 10dB coupler, which splits the output signal into coupled signals and sends them to a power meter for power monitoring and output signal transmission testing. The power meter monitors the coupling degree of the power compensation coupler. The coupling flatness is ±1dB, the port VSWR is ≤1.2, and the insertion loss is ≤1dB.

[0172] In the high-frequency front-end device based on OIP3 testing, the programmable attenuator is an E-band high linearity programmable attenuator that dynamically reaches -35dB, achieving linear modulation of the output signal.

[0173] In high-frequency front-end devices based on OIP3 testing, the programmable attenuator is remotely controlled via a GPIB interface. After the driver is installed, control commands are sent through automated testing software to set the attenuation amount, typically in dB. In OIP3 testing, parameter settings can be implemented using step attenuation, with 1 dB steps adjustable within a power range of -22 dBm to +12 dBm.

[0174] In high-frequency front-end devices based on OIP3 testing, waveguide cavity structures are used for combiners, couplers, and isolators to ensure overall linearity, thereby ensuring the accuracy and consistency of internal connections. Electromagnetic simulation software is used to optimize the device structure and reduce reflection and radiation losses.

[0175] In the high-frequency front-end device based on OIP3 testing, the combiner adopts a Magic-T form, consisting of four ports. The horizontal arm is used for input or output signals; the vertical arm is used for input or output signals; and the symmetrical arms (port 1 and port 2) are typically used for signal distribution or combining. Within the Magic-T's internal waveguide, a stepped impedance transformer is used to gradually change the waveguide impedance to reduce reflections and achieve matching. The high and low output channels are input to the symmetrical arms (port 1 and port 2) of the combiner, and in-phase signals are combined and output at the vertical ratio.

[0176] In the high-frequency front-end device based on OIP3 testing, the coupler uses a waveguide structure with a coupling aperture to achieve signal transmission through electromagnetic field coupling. It consists of three ports: port 1 (input) for signal input; port 2 (output) for signal output; and port 3 (coupling) for signal coupling output. When the signal passes through the main transmission line, the electromagnetic field leaks to the auxiliary transmission line through the coupling aperture. Due to the design and position of the coupling aperture, the signal propagates in only one direction in the auxiliary transmission line, thus achieving directional coupling. The coupling aperture is circular, and impedance transformation is achieved through a λ / 4 transmission line to match the impedance of the input and output ports.

[0177] In the high-frequency front-end device based on OIP3 testing, the isolator adopts a waveguide structure and ferrite material with high-frequency characteristics to achieve unidirectional transmission. It consists of two ports: port 1 (input terminal) for signal input and port 2 (output terminal) for signal output, ensuring low forward loss and high reverse isolation.

[0178] like Figure 5 As shown, this method is as follows:

[0179] Step 1: Accurately calibrate the nonlinear characteristics, channel synchronization, and temperature effects of the system by injecting dual-tone signals, measuring time delays, and modeling temperature compensation.

[0180] Step 2: Employ dual-loop power control, time delay tracking, and intermodulation component extraction techniques to ensure signal stability, phase synchronization, and accurate intermodulation component analysis.

[0181] Step 3: Process multi-dimensional data using the three-slope method and weighted average to accurately calculate OIP3 and evaluate the reliability of the results.

[0182] Step 4: Design a multi-level overpower protection and phase-locked loop recapture process to ensure stable operation and automatic recovery of the system under abnormal conditions.

[0183] In one specific implementation, the high-frequency front-end device of this invention first divides the input signal into two channels: a high-power channel and a low-power channel. The input signal of the high-power channel is converted to the target frequency by a 6th-order frequency multiplier, with an output power of +17dBm. This signal undergoes power adjustment via a manually adjustable attenuator and is then sent to the IN1 port of the combiner via an E-band isolator. The low-power channel, on the other hand, converts the input signal to the target frequency through another 6th-order frequency multiplier, with an output power of +15dBm, and is then sent to the IN2 port of the combiner after passing through an E-band isolator. The combiner combines the signals from the two channels and outputs the combined signal to an E-band unidirectional coupler.

[0184] The E-band coupler is used for power monitoring, enabling real-time acquisition of the combined signal power. Simultaneously, its direct-output signal is adjusted by an E-band programmable attenuator, with an attenuation range from 0dB to -35dB, achieving precise adjustment of the output signal. This process allows for flexible adjustment of the output signal amplitude while maintaining high dynamic range and stable linear modulation, avoiding nonlinear distortion of the signal.

[0185] In practical applications, users can choose single-channel mode as a frequency extension source, or input signals of the same frequency or any frequency difference for combined output in dual-channel mode, thereby completing the testing of E-band OIP3 and IM3. By employing 6th-order frequency multiplication technology, this device can effectively suppress high-order harmonics and reduce the impact of harmonic components on signal quality. The design of the highly directional combiner and isolator ensures the independence between signals, avoiding signal crosstalk and unnecessary intermodulation products.

[0186] During OIP3 and IM3 testing, each stage of the signal can be monitored in real time. By precisely adjusting individual components, such as manually adjustable attenuators and programmable attenuators, the amplitude, power, and frequency of the output signal can be ensured to remain within predetermined ranges, and different testing requirements can be met. This solution offers high flexibility and can be optimized and adjusted according to specific testing scenarios.

[0187] The above-described specific embodiments are merely preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Various modifications, substitutions, and improvements made by those skilled in the art to the technical solutions of the present invention based on the provided textual description and drawings, without departing from the design concept and spirit of the present invention, should all fall within the scope of protection of the present invention. The scope of protection of the present invention is determined by the claims.

Claims

1. A high-frequency front-end device testing method based on OIP3 testing, characterized in that, Step 1: Precise calibration of nonlinear characteristics, channel synchronization and temperature effects through dual-tone signal injection, time delay measurement and temperature compensation modeling; Step 1 is as follows: Step 11: Input the base frequency signal to the high channel and the low channel at the same time, and convert the base frequency signal into the target frequency through frequency multiplication; then, add or subtract a certain frequency offset on the base frequency, ranging from 1MHz to 50MHz, to capture the nonlinear effects of the system; Step 12: Collect five key frequency points at the output end, including two signals after frequency offset, intermodulation components and center frequency, and the data is used for subsequent nonlinear coefficient extraction; according to the collected data, the coefficient matrix reflecting the nonlinear relationship of the signal is solved by the least squares method; Step 13: Calculate the time delay difference between the high channel and the low channel by injecting a linear frequency modulation signal and using a cross-correlation algorithm, which helps to detect the signal peak value and determine the time delay difference; according to the calculated time delay difference, generate the corresponding phase compensation table for each frequency point; Step 14: Under different temperature conditions, heat the frequency multiplier and record the change of output power; through the record of temperature change, the relationship between output power and temperature is obtained, a compensation curve is fitted through temperature change data, according to the curve, the influence of temperature on power is calculated, and the corresponding compensation coefficient is obtained, which is used for subsequent temperature correction; Step 2: Adopt double-loop power control, time delay tracking and intermodulation component extraction technology to ensure signal stability, phase synchronization and accurate intermodulation component analysis; Step 2 is as follows: Step 21: Adopt a double-loop control structure, the outer loop is responsible for coarse power adjustment, and the gain is adjusted by comparing the actual power with the target power; the inner loop performs fine adjustment, and the auxiliary coupling end power is continuously adjusted through the PID control algorithm to ensure that the system reaches a stable state; Step 22: In order to compensate for the power distortion caused by nonlinear effects, the system adjusts the output power in real time, and compensates the power through a correction factor to ensure that the measured power is close to the ideal value; Step 23: Every 10ms, inject a pulse signal and update the time delay difference by detecting the peak time of the signal; according to these updated information, the time delay difference of the signal is accurately adjusted; after updating the time delay difference, the required phase compensation is calculated and the phase of the system is adjusted in real time to ensure the synchronization of the signal; Step 24: Use blind source separation algorithm to extract intermodulation components from the collected signals, which separates the intermodulation components and other noise components generated by nonlinear effects; after extracting the intermodulation components, remove the noise base through the adaptive threshold algorithm to obtain the true intermodulation component power, so as to more accurately calculate OIP3; Step 3: Accurately calculate OIP3 and evaluate the reliability of the results by three-slope method and weighted average processing of multi-dimensional data; Step 4: Design multi-stage over-power protection and phase-locked loop recapture process to ensure stable operation and automatic recovery of the system under abnormal conditions.

2. The method of claim 1, wherein the OIP3 test-based high frequency front-end device testing method is characterized by, Step 3 is as follows: Step 31: At different power levels, use the three slope method to calculate OIP3, OIP3 is estimated by the difference between the fundamental frequency power and the intermodulation component power, which is used to measure the linear range of the system, and through three different calculation methods, the double tone equal amplitude method, the power extrapolation method and the noise base method, the OIP3 value is weighted average, and the final OIP3 value is obtained; Step 32: Calculate the uncertainty of the measurement results, including the measurement errors of power, phase and temperature, and through the analysis of these error sources, the total uncertainty is obtained; Step 33: Determine whether the OIP3 calculation result is valid by judging whether the standard deviation of three measurements and the intermodulation ratio IMR meet the set standard.

3. The high-frequency front-end device testing method based on OIP3 testing according to claim 1, characterized in that, Step 4 is as follows: Step 41: Design a multi-stage over-power protection mechanism, when the output power is detected to be out of limit, take step-by-step response measures; Step 42: When the system loses phase lock, the phase-locked loop recaptures the flow.

4. A high-frequency front-end device based on OIP3 testing, suitable for the high-frequency front-end device testing method based on OIP3 testing of any one of claims 1-3, characterized in that: It comprises a high-power channel 6 times frequency multiplier (1) with an output power of +17dBm, a high-power channel manual adjustable attenuator (3), a high-power channel E-band isolator (4), a low-power channel 6 times frequency multiplier (2) with an output power of +15dBm, a low-power channel E-band isolator (5), a combiner (6), an E-band coupler (7), and an E-band programmable attenuator (8), wherein: The input signal of the high-power channel is sent to the manual adjustable attenuator (3) after passing through the high-power channel 6 times frequency multiplier (1), and is sent to the combiner (6) IN1 port after passing through the high-power channel E-band isolator (4); The input signal of the low-power channel is sent to the combiner (6) IN2 port after passing through the low-power channel 6 times frequency multiplier (2) and the low-power channel E-band isolator (5); The combiner (6) combines and outputs the two signals, and sends them to the E-band coupler (7); The E-band coupler (7) performs power monitoring and sends the signal to the E-band programmable attenuator (8) through the straight-through output, and outputs after attenuation, thereby realizing linear output modulation.

5. The high-frequency front-end device based on OIP3 testing according to claim 4, characterized in that: The input channels are two independent channels, high-power channel and low-power channel; both the high-power channel and the low-power channel use 6 times frequency multiplier, the output power of the high-power output channel is +17dBm, the output power of the low-power output channel is +15dBm, and the output frequency range is 60GHz to 90GHz.

6. The high-frequency front-end device based on OIP3 testing according to claim 4, characterized in that: A manual adjustable attenuator is arranged in the high-power output channel, and the attenuation range is 0dB to -30dB.

7. The high-frequency front-end device based on OIP3 testing according to claim 4, characterized in that: The E-band programmable attenuator is a high-linearity programmable attenuator, and the attenuation range is 0dB to -35dB.

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