A tunable single-passband microwave optical filter is realized based on the stimulated Brillouin scattering and phase modulation.When only one pump signal is introduced,the tuning range of the filter is 0.5 to 18.3GHz.When only one laser is used,and pump signal is achieved by intensity modulation of the microwave signal added at intensity modulator,the stability of the filter system is better than that of the system whose two lasers are used as light carrier and pump signal respectively.When introducing two pump signals whose frequency interval equals the two times as large as the stimulated Brillouin frequency shift,the tuning range of the filter is 0.9 to 31.3GHz.

The phase property is an important parameter of the intense relativistic klystron amplifier (RKA).But the intense relativistic electric beams (IREBs) with a long rise time in terms of high-power pulse power source will cause the output microwave phase jitter when driving the RKA,which limits the RKA's applications.Based on the intense current pulse electron beam properties,the impacts on output microwave phase by the increase of the electron beams' energy in the front section of the pulse and the spurious frequency caused by energy change in the cavities are analyzed through the theory.And then some PIC simulations and experiments are studied.It is found that the increase of the electron beams' energy in the front section lead to the output microwave phase continually changing.Besides,the spurious frequency in the cavity caused by the front section of the electron beams,which lead to the output microwave phase continually jitter in the front and the early of the stable section of the pulse.In the condition of cavities' parameters are constant,the output microwave phase is significantly affected by the rate of electron beams energy in the front section:when the rate of electron beams energy increase,the amplitude of the phase jitter and the jitter duration increase.And the stabilization of the phase can be increased by reducing the Q of the cavity at the frequency point of the spurious frequency.

A class of planar bandpass filters (BPFs) using dual/triple-mode substrate integrated waveguide (SIW) resonator and ground coplanar waveguides (GCPWs) are proposed according to miniaturization and high selectivity. The quasi-elliptic, asymmetric and non-transmission zero (TZ) response dual-mode SIW filters can be realized by changing resonance frequencies of TE₁₀₂ and TE₂₀₁, and the external couplings. Two GCPWs of the same size are etched on SIW cavity top metal plane;and the TE₁₀₂, TE₂₀₁ and two GCPWs in a single SIW cavity are combined to construct the diversified response fourth-order filters. On the basis of asymmetric and non-TZ response, the fundamental mode TE₁₀₁ can be shifted to the passband to form a fifth-order filter with wider bandwidth. The designed BPFs were fabricated and measured;and the simulated and measured results agree with each other, demonstrating the feasibility of using hybrid dual/triple-mode SIW and CPWs in a single cavity to design BPFs.

Bandpass filters (BPFs) with generalized Chebyshev response using dual-and single-mode substrate integrated waveguide (SIW) resonators are proposed according to the miniaturization and high performances.The box-like topology with an additional cross-coupled path realized by the fundamental mode (TE₁₀₁) of the dual-mode SIW cavity is proposed,and an additional transmission zero (TZ) is achieved.The traditional negative coupling structure is not required in the proposed structure,and two TZs can be realized;moreover,the structure has flexible responses that two TZs can be located on the lower and/or upper of passband.To improve the selectivity,a complementary split-ring resonator (CSRR) etched into the fourth-order SIW filter to design a filter with an extended box-like topology is studied,and the fifth-order filtering function with three finite TZs can be realized.To verify the feasibility,a symmetric and an asymmetric response fourth-order BPFs with center frequency of 10GHz and a fifth-order BPF with center frequency of 5.8GHz are designed.The corresponding coupling matrixes of box-like topologies with nonresonating node (NRN) are also given to verify the proposed structure.Finally,the designed SIW BPFs are processed and measured.The responses of coupling matrixes,simulated and measured results are in good agreement,which demonstrates the feasibility of designed filters with high performances using the proposed structures.

This paper describes a L-band 400W gallium nitride (GaN) internally matched power amplifier using an accurate large signal Angelov model. The large gate-periphery GaN devices on SiC substrate are used for achieving the large output power and high efficiency. For designing exactly the power amplifier, the large signal GaN model is founded using measured pulse I-V and S parameters of different bias conditions. Based on the large signal model, the input and output matching circuits and one 55mm GaN transistor are integrated in a 17.4mm×24mm ceramic package. The amplifier finally has the pulse output power of over 400W, the power gain of over 15dB across the band of 1.2-1.4GHz and the max power added efficiency is 81.3% under the pulse drain bias voltage (Vds) of 48V, the duty is 10% with the pulse width of 100μs. The results show that the character of realized amplifier is consistent with the simulation result, which fully indicates the veracity of the developed model. And this is the most highest efficiency of a 400W power amplifier achieved in L-band.

The nondestructive and high-resolution near-field distribution imaging of microwave and millimeter wave chips is very important for the function and failure analysis of RF chips. This experiment is based on the unique quantum system of diamond NV (nitrogen-vacancy) color center. A diamond sample with a diameter of about 14 μm is selected and adhered to the tapered tip of a 20 μm fiber. A high-resolution, non-destructive and miniaturized probe is prepared by analyzing the ground state spin evolution law of NV color center in the change of microwave field, and the all optical method is used. The whole field distribution on the chip surface is obtained by imaging. In this paper, the near-field distribution image of GaN high electron mobility transistor is given. The ODMR spectrum and Rabi spectrum are fitted, and the imaging results are analyzed. This system has the advantages of high efficiency, high resolution, high sensitivity and low near-field interference. It is expected to provide a new scheme for the application of high integration microwave circuit fault diagnosis, antenna radiation profile, microwave integrated circuit electromagnetic compatibility test, etc.

Millimeter wave traveling wave tubes are potentially effective and feasible power amplifier solutions for high data rate wireless communication. Research projects of high data rate wireless communication technology based on millimeter wave traveling wave tubes, whose operation frequency ranges are between 71 GHz and 300 GHz, are being developed abroad. The development of millimeter wave traveling wave tubes between 71 GHz and 235 GHz are presented. The enabling technologies of these devices are also overviewed, such as microfabrication of slow wave structures, novel design of slow wave structures and transmission with broadband and low loss.

Wideband electro-optic phase modulator (PM) is a critical component for the applications of coherent optical communication, microwave photonics signal generation, processing and measurement, due to the advantages of bias-free, linear modulation and low insertion loss. Modulation index and half-wave voltage are key parameters to assess the performance of PMs. However, the conventional mothed based on optical spectrum analyzer (OSA) surfers from low and measurement dead-band. To overcome these problems, a self-calibrated and high-resolution method for the measurement of PM is proposed based on UV-ESA. The modulation index and half-wave voltage are achieved by analyzing the electrical beat notes of the detuned optical carrier and the phase modulation sidebandswith two different driving voltages in the same driving frequency. Moreover, it verify the validity of proposed mechod without dismantling the measurement link and eliminates the need of assisted wideband devices or instruments. The measured results are also compared with those based on OSA to check for effectiveness and consistency of accuracy.

In order to meet the needs of integrated microwave devices for high-resolution microwave near-field measurement, this paper proposes a microwave near-field imaging technology based on the diamond Nitrogen-Vacancy (NV) color center. This technology can be used to find interference sources and signal crosstalk of integrated microwave devices such as chips. This microwave near-field imaging method uses diamond NV color center particles as a field sensor, where the diamond particles are fixed at the end of a tapered fiber. Due to the Zeeman effect, the optical detection magnetic resonance (ODMR) spectrum of the NV color center will split into 8 peaks in the external static magnetic field environment. By measuring the Rabi oscillation spectrum of the resonance peak frequency point, the Rabi frequency can be obtained, and then use 2.8MHz/Gauss to calculate the microwave field strength. Finally, the near-field image of the surface microwave field of the chip and the integrated microwave device can be obtained by performing two-dimensional image processing on all measured data points.

Phase shifter is the core device of phased array radar (PAR). With the gradual increase of the working frequency, the insertion loss and phase control error of the traditional phase shifter get worsen seriously, resulting in additional power consumption and poor beam performance. In this paper, a high-precision digital phase shifting method based on CP-PLL is investigated. Based on the analysis of CP-PLL mathematical model and phase-shifting mechanism, the method of numerical control current source is proposed to realize the accurate control of the output signal phase, the circuit model is established to carry out simulation analysis, and the experimental circuit module is designed. The effectiveness and accuracy of the method are verified by the comparison of simulation and measurement. The results show that the phase-shifting step is better than 1°, and the accuracy is better than 10% of the phase-shifting value. The CP-PLL can be used in PAR as a local oscillator or as a direct transmitter signal. It has the characteristics of high precision, low power consumption and easy integration, which can replace the phase shifter and effectively improve the performance of PAR.