A summary of a 140 GHz inverse synthetic aperture radar (ISAR) is presented. High resolution and real time imaging are two key points in the design. Using the frequency-modulated continuous-wave (FMCW) radar technique with a 5 GHz bandwidth, 3 cm range resolution is achieved with assistance of software calibration compensating for nonlinearities of the LFM waveform. In cross-range region, synthetic aperture technique is adopted to improve imaging resolution. Real time imaging capability is enabled by using a hardware structure constructed with FPGA+CPU+GPU in signal processing unit. The final system was used to get ISAR image of a rotating target at 5 m. The 2-D (range and cross-range) imaging resolution is 3 cm × 3 cm with a real time image frame rate of 5 Hz.

Real-Time Imaging With a 140 GHz Inverse Synthetic Aperture Radar

Influence of periodic structure and pixel area on the performance of antenna‐coupled Nb5N6 array detector

This paper described the design and tested results of the pill-box window for the 0.67THz travelling wave tube (TWT) with the help of 3-D simulation software. The test results show that the design of the pill-box window satisfied the need of the TWT. The S21 parameter is -3.1 dB, and the S11 parameter is less than -10 dB from 649GHz to 672GHz. It bases the manufacture of the 0.67THz travelling wave tube.

Design and experiment of the pill-box window for 0.67THz TWT

This paper described the design and tested results of the pill-box window for the 0.67THz travelling wave tube (TWT) with the help of 3-D simulation software. The test results show that the design of the pill-box window satisfied the need of the TWT. The S21 parameter is -3.1 dB, and the S11 parameter is less than -10 dB from 649GHz to 672GHz. It bases the manufacture of the 0.67THz travelling wave tube. 

The folded-waveguide oscillator can get higher output power than the BWOs. This paper shows the design results of the 0.22THz folded-waveguide oscillator. The design has been conducted using analytic Pierce theory and time-domain simulations. The simulated results shows the maximum output power of the oscillator can reach 5W with the 18kV/50mA electron beam. The electric tunable bandwidth is about 1GHz in the range of 0. $\pmb{219}\mathbf{THz}\sim \pmb{0.22}\mathbf{THz}$ .

Design of 0.22THz Folded-Waveguide Oscillator

The design and realization of a terahertz(THz) radar system with 0.14 THz carrier frequency and 5 GHz bandwidth have been presented. The Ka band signal was frequency-doubled to be used as the local oscillator signal for sub-harmonic mixer in the systems transceiver chain. For the transmitted signal was a linearly frequency-modulated continuous-wave(LFM-CW), the dechirp technique was used in the THz radar receiver front end. By using this THz radar system, 3 cm high resolution range profiles were obtained as well as inverse synthetic aperture radar(ISAR) images, which exactly represent the subtle features of targets.

Yao Jun

Papers

Experimental research on high resolution terahertz radar imaging