Sun Houjun

Numerical Simulations of Backward-to-Forward Leaky-Wave Antenna with Composite Right/Left-Handed Coplanar Waveguide

A composite right / left-handed (CRLH) coplanar waveguide (CPW) structure and its leaky-wave antenna (LWA) with continuous backward-to-forward scanning applications are proposed. The structure of the CRLH transmission line (TL) is composed of split-ring resonators (SRRs) for left-handed (LH) series capacitance and short-circuited stubs connected between the CPW central signal line and the ground for LH shunt inductance, while the unavoidable right-handed (RH) parasitic effects series inductance and shunt capacitance are generated by wave propagation through the host transmission line. The dispersion relations are calculated and compared with the equivalent circuit model method and 3D full-wave simulations, which can be used to determine the physical dimensions of the CRLH-CPW, such as in the balanced CRLH-TL case. As a main example, a CRLH-CPW-LWA operating from 1.67 GHz to 1.80 GHz with the dispersion characteristics of the balanced CRLH-TL case shows continuous leakage frequency band (fast wave region) from LH (phase constant β 0, 1.74 0).

Research on RCS measurement under non-far field condition

While stealth technologies for large scale targets were researched, RCS static measurement method was adopted, which is often used under non-far field condition. Therefore a theoretical premise was deduced, and a stepped frequency pulse compression system was designed for RCS measurement, especially a novel RF channel was designed to keep the system stable. Not only the simulation but also the experimental result is presented LU the paper; at the same time, some practical difficulties are designated.

Design and simulation of a W-band two-way power divider based on substrate integrated waveguide

Substrate integrated waveguide (SIW) is a new type of waveguide structure, which has a lot of advantages on high Q, low loss, low radiation and so on. Because of its unique structure, it is very easy to be integrated in the planar circuits. This paper mainly introduces an efficient type of transition between SIW and rectangular waveguide, and a two-way SIW power divider at w-band. Using full-wave simulation shows that the w-band two-way SIW power divider can work in the bandwidth of 91-95GHz, with less than -15dB, and S21, S31 between -3dB and -4dB.

Study of the Improved MM-Wave Omni-directional Microstrip Antenna

Microstrip antennas possess some attractive features such as low profile, light weight, small volume and low production cost. Meanwhile, most conventional mm-wave omni-directional antennas use waveguide or dielectric antennas which have some shortcomings comparing with microstrip antennas. An improved mm-wave omni-directional microstrip antenna is presented in this paper. Two directors are added beside an open-circuit terminal microstrip line. Therefore, the antenna shows better omni-directional performance. The simulated and measured results are demonstrated and discussed.

Hardware-in-the-Loop simulation and testing system for Millimeter-Wave seeker

The implementation of integrated hardware-in-the-loop (HWIL) simulation and testing system for millimeter-wave (MMW) seeker was presented. The system can implement dynamic real-time testing for MMW seeker. The seekers ability of detecting, identifying and tracking the target, can be checked and tested in a realistic flight scenario. The system configuration is described, and the implementation of its chief components was proposed which are the MMW scene generator, the high speed data acquisition subsystem, and the central control unit. This system could be applied to the simulation and testing of some types of MMW seeker which are on development.

Stepped Frequency Millimeter-wave Signal ISAR Processing

Radar target characteristics are usually measured using stepped frequency signal, a millimeter-wave system is designed and ISAR processing technology is investigated. In order to gain two dimension scattering centers distribution, range Doppler algorithm is used, then, CBP algorithm is verified to obtaining target shape information more efficiently.

Dual-frequency Scattering Measurement System for Radar Cross-Section Imaging

X band and Ka band front-ends are integrated into one measurement system in order to get radar cross section and images of complex objects, software defined radio is applied in system design. Then ISAR processing technology is investigated to gain two dimension scattering centers distribution and radar cross section imaging and CBP algorithm is verified to obtaining object information efficiently.

Design of three-dimensional balun based on LTCC technology

Balun, which means balanced-to-unbalanced transformer, is widely used in wireless communication systems. Balun can transform an unbalanced input signal into balanced output having equal magnitudes, 180° phase shift and vice-versa. As miniaturization is an inevitable trend of the development of todays electronic devices, the study of the miniaturization of balun is of great significance. To realize the miniaturization of balun, a three-dimensional structure to design based on LTCC technology is used in our design. The frequency range of this balun is 1.1-2.5GHz, the amplitude unbalance is lower than 0.4dB, and the phase unbalance is smaller than 4 degree. The advantage of this design is of its small size and nice balance feature.

Comparisons of ISAR Time-frequency imaging methods

Time-frequency imaging methods include many base functions, it is hoped that the best can be applied in two dimensional imaging. A experimental radar system is designed. STFT, WVD Harr and morlet wavelet transforms are simulated and compared, which shows WVD has the best quality of the ISAR images.

The System Design of a Small Caliber MMW Earth Observing Radar

To attain a small caliber millimeter-wave earth observing radar, a wide-band miniature MMW system is needed. In this paper, the miniature system design of a frequency-modulated stepping MMW radar is presented. Firstly, this miniature radars advantage is analyzed for the need of small caliber earth observing missile. Then, the system configuration is provided to obtain the high range resolution and miniaturization. And in the meanwhile, the method to solve new system problems and optimized selection of system parameters is discussed according to the small caliber terminal guidance radar. At last, experiment results are also given to proven the designed system s performance.