C-band low-loss phase shifter >360° for WLAN applications

This paper presents a single-stage 5.5-6.0 GHz reflection-type phase shifter based on a complex load design and Schottky varactor diodes. The measured phase shift is > 360deg at 5.8 GHz with an average insertion loss of 1.7 dB. The measured reflection coefficient is better than -17 dB at 5.8 GHz over all bias voltages. The phase shift is 440deg at 5.6 GHz with an associated insertion loss of only 2.1 dB and a reflection coefficient better than -13 dB. At 5.9 GHz, the phase shift reduces to 315deg which is equivalent to a 3-bit design with an insertion loss of still < 2.0 dB. The phase shifter results in state-of-the-art performance and is suitable for WLAN smart antennas at the 5.5-6.0 GHz.