Antenna with switchable linear polarization for 60 GHz

An antenna with switchable linear polarization is presented. This antenna has two input ports. One for RHCP and one for LHCP. The linear combination of both circular polarization waves with equal amplitude will result in a linear polarization while the phase difference between them controls the direction of linear polarization. With 2-bit phase shifter at 0°, 90°, 180° and 270°, this antenna can synthesis linear polarization at 0°, 45°, 90° and 135°. The measured -10dB input matching bandwidth is about 61~66GHz. Measured antenna gain when switched to x- and y-polarization are about 7 and 8 dB respectively.