A novel quasi lumped-element resonator using a left-handed transmission line section

The paper presents a novel miniaturized resonator configuration that employs a left-handed transmission line (LHTL) section. It is shown that combining right-handed and left-handed TLs can result in a compact resonator with a remarkable spurious performance. The paper employs the LHTL concept as a design tool to combine distributed TLs and lumped element components to realize a novel resonator structure. The proposed resonator consists of two distributed TLs that are connected through a 1-unit cell LHTL. The resonant frequency and quality factor of the proposed structure are measured. In comparison with the conventional λ/2 resonator, the proposed resonator offers 5 times size reduction. A three-pole filter is designed, fabricated and tested employing the proposed resonator.