Adaptive phased array antenna based on NMOS phase shifter for Intelligent Transport System application

In this paper an adaptive phased array based on NMOS phase shifter is presented. The main beam of the adaptive antenna can be steered ± 30° by controlling the bias voltage of the NMOS based variable phase shifter which is required to detect the blind spot zone in Intelligent Transport System. This transceiver consists of four inset fed rectangular microstrip patch antennas with four different phase angle excitation. Four different phase angles are generated from the same source by using four symmetrical phase shifter by properly adjusting their bias voltage. To maximize the gain and to reduce the side lobe level, the patches are also fed with Chebyscheff polynomial based current distribution technique. Two different case has been studied, one beam angle at 15° and another at 30° from its broad side direction. For both the angles of main beam, the gain of the adaptive phased array antenna is found to be 11.7dBi and 10.5dBi respectively.