Lei Zhenya

EMC analysis for Multi-point grounding cable of aircraft

In a real-life airplane, there are usually a large number of electronic devices and radiation sources. Equipped in this complex electromagnetic environment, the conducting cables always produce serious impact on the electromagnetic performance of the aircraft system. Therefore, it is of importance to investigate the electromagnetic compatibility (EMC) of the cables. To this end, we propose a simple and accurate approach in this paper. With the method, the cables are modeled as Multi-point grounding transmission lines. The surface current on the cables can be obtained by employing the theory of images. Subsequently, the radiation pattern can be efficiently calculated with full-wave algorithm of frequency domain. We propose to give the key points of reducing the electromagnetic radiation of cables with analysing the certain instances. The method is easily implemented and well-suited for the EMC optimization design of aircrafts.

An Accurate Mutual Coupling Calculation For Microstrip Antennas For Impedance Mismatching

An exact determination of mutual coupling between microstrip patches is presented in this paper. The classical formula for mutual coupling based on multi-port network theory is popular for determining such coupling. However, this formula ignores the impedance mismatching between antenna and its load. In this presentation an accurate formula for the coupling between patch elements is deduced. For impedance matching case the exact formula reduces to the classical formula. The simulation results show that the consideration of impedance mismatching in mutual coupling calculation is very important.

Research on the method for producing a highly linear FMCW signal based on the PLL circuits

This paper describes a method for directly generating FMCW signal based on the PLL circuits; mainly by changing the PLL systems frequency divider ratio N rapidly and producing a corresponding control voltage to control VCO to output the FMCW signal. The key of this method is the transition period Δt of divider. Set up simulation model in ADS2011 to simulate, get the conclusion that the smaller the transition period Δt, the better the linearity of the FMCW signal than verify this conclusion by measurement. This method has many characteristics like high reliability, easy to adjust, mature circuit structure, etc.

Variational method to analyze the equivalent network of a rectangular dielectric post in a rectangular waveguide

The equivalent filter modeling of a rectangular dielectric post in a rectangular waveguide is obtained through the variational expression of input impedance. The reflection coefficient expressed in components of network is in good agreement with the results given by K. Siakavara, et al. (1991), The method can be applied to design filter.