Dual-band sub-harmonic quadrature mixer using composite right∕left-handed transmission lines

Abstract

A dual-band (DB) sub-harmonic quadrature mixer using composite right/left-handed (CRLH) transmission lines (TL) is presented. The CRLH-TLs are used to provide dual-bandwidth operation in the Wilkinson power dividers (WPDs), the ±45° delay line for in-phase/quadrature generation, and the sub-harmonically pumped mixers. Theory and implementation of the RF/LO DB-WPDs, the dual-passband dual-stopband (DPDS) shunt terminations, and the DB sub-harmonically pumped mixers (SHPMs) are presented. These DB microwave components for the DB quadrature mixer are detailed in individual sections with both simulated and measured performances. The DB-WPDs exhibit S21 and S31 larger than −3.95 dB, return losses larger than 12 dB, isolations larger than 16 dB, phase imbalance less than 2.15°, and gain imbalance less than 0.25 dB at each passband. The DPDS terminations demonstrate insertion loss larger than 16 dB at stopbands and less than 2.3 dB at passbands. The DB-SHPM shows 10 dB and 11.7 dB conversion loss in low- and high-frequency mixing schemes with good linearity. Local oscillator (LO) to radio frequency (RF) isolation larger than 30 dB is also measured in both frequency mixing schemes. The measured results of the DB quadrature mixer display output amplitude balance, orthogonal characteristic, and LO to RF isolation larger than 45 dB.