Novel combined diversity antenna for OFDM

Electric field varies enormously when digital broadcasting terrestrial signal is received in mobile environments. Therefore, the diversity receiver is indispensable to a television receiver mounted on the vehicle to overcome this phenomenon. Especially, combined diversity technology by digital beam forming (DBF) is employed for the high definition TV to secure high CNR. In this case, since several receivers are used, receiver for vehicle is 3 to 4 times of prices comparing with the home-use receiver. In addition, the watching time draws in for such mobile equipment as notebook PC because of high power consumption. Receiver using phased array or ESPAR has single receiving channel. However, when we use this type of antenna, we must adopt the blind algorithm for adaptive beamforming as we cannot observe signals of each channel. We cannot operate the blind algorithm in mobile environment because of huge convergence time. And, the phase shifter or variable reactor is set in probation. This situation is equivalent to fast change of channel. Therefore, out of synchronization is occurred and BER degrades.