In this letter, we present a method for improving the front-to-back ratio (FBR) of a broadcast antenna. The digitalization of terrestrial TV demands more efficient channel usage due to the reduction in TV bands after the switch-over. Thus, we designed an antenna with an FBR improved over -45 dB as compared to the -20 to -25 dB FBR range of existing antennas. We show experimentally that this antenna satisfies the required performance.

In land mobile communication, CMA (Constant Modulus Algorithm) has been studied to reduce multipath fading effect. By this method, the transmitted power is not used efficiently since all the multipath components have the same information. To make use of received power efficiently, we propose a Blind Multiple Beam Adaptive Array. It has the following three feature points. First, we use CMA which can reduce the multipath fading effect to some extent without training signal. Second, LMS algorithm which can capture the multipath components which are separated from the reference signal by some extent. Third, we use FDF (Fractional Delay Filter) and TED (Timing Error Detector) loop which can detect and compensate fractional delay. As a result of utilizing the multipath components which is suppressed by CMA, the proposed technique achieves better performance than CMA adaptive array.