Analysis and Design of Novel 2-D Transmission-Line Metamaterial and Its Application to Compact Dual-Band Antenna

A novel 2-D transmission-line metamaterial (TL-MTM) is proposed consisting of two-turns complementary spiral resonators (CSRs) and mushroom structure. For characterization, the circuit parameters are extracted, and the unique 2-D left-handed characteristics are theoretically investigated and further verified by eigenmode calculation. Moreover, a concept of compact factor measuring the miniaturization degrees is first proposed, indicating an efficiency method toward the design of electrically smaller structures. For application, a dual-band and dual-mode antenna operating at n=0 (2.4 GHz, Bluetooth band) and n=+1 (3.5 GHz, WiMAX band) is designed, fabricated, and measured by inserting a 2-D CSRs-loaded TL-MTM cell into the conventional microstrip patch. As a result, the antenna exhibits good impedance matches at both bands feeding with a two-annular-rings slot and comparable radiation gains of 2.45 and 7.65 dB. Also, the antenna is compact, occupying an area of only 0.16λ₀ × 0.16λ₀. In addition, it is more convenient to realize frequency manipulation by inserting CSRs.