This paper presents a 30 GHz tunable transformer-based duplexer with dual-antenna configuration. By using orthogonal linearly-polarized antennas and the transformer-based duplexer, the transmitter and receiver duplexes the two antennas with orthogonal circularly-polarized signals. Furthermore, magnetic tuning is introduced to improve isolation in case of practical imbalances. Measurement results demonstrate an isolation of > 50 dB by the duplexer for 1 GHz bandwidth. The achieved noise figure (NF) is 4 dB and insertion loss in the TX path is 3.1 dB. The tunable duplexer occupies an active area of 0.25 mm × 0.25 mm.
|Title of host publication||IEEE Custom Integrated Circuits Conference, 15-17 September 2014, San Jose, California, USA|
|Place of Publication||Piscataway|
|Publisher||Institute of Electrical and Electronics Engineers|
|Publication status||Published - 2014|