A Novel 1 × 4 1-Bit Circularly Polarized Phased Array Antenna for Millimeter-Wave Application

In this letter, a novel 1 × 4 1-bit circularly polarized (CP) phased array antenna is proposed for millimeter-wave applications. The proposed array antenna consists of four 1-bit phase reconfigurable CP antennas with fixed phase distribution. The CP element contains a CP magnetoelectric (ME) dipole antenna and a 1-bit phase feeding structure. The 1-bit feeding structure is achieved by the slot line to asymmetric substrate integrated coaxial line (SICL) transition loaded with a pair of PIN diodes (two phase states: 0° and 180°). As the different phases are obtained by rotating the CP antenna at various angles, the fixed initial phase distribution can be easily realized. A prototype is fabricated and measured for validation. The measured results show that the impedance and AR bandwidth of the proposed array antenna are 12.3% from 26.5 to 30 GHz. In the frequency range of 26.5-30 GHz, the array antenna can steer the beam from -38° to 38°, with the maximum realized gains of the four steer angles being 7.68, 6.99, 7.35, 6.05, and 5.61 dBic, respectively. The proposed antenna can serve as a good candidate for wireless communication with low cost and low power consumption.