This paper reports the design procedure and critical discussion about the relation between the input impedance and bandwidth for obtaining the wide-band, thin film scatter type microwave absorber in the x-band range. A design method of double-layered absorber was provided by means of transmission line theory. The authours have developed a scatter type method using thin dipole AL metal which are put loss dielectric based on a metal. From the experimental results, it is concluded that the amounts of reflection agree well with results from theoretical calculation.
This paper reports a threshold extension method for Direct Broadcasting Satellite [DBS] Reception. Some threshold extension methods for frequency modulation [FM] have studied, but the improved level of these methods is only 1-2dB in NTSC color picture and this is insufficient for DBS reception. The picture quality is improved below threshold level of DBS signal by using following three methods. The first method is the limitation of the bandwidth of the DBS signal. The second method is regeneration of synchronizing pulse of the demodulated television signal. The third method is the replacement of impulse noises. The DBS signal of C/N=4dB can be received using these methods.