Frequency Reconfigurable and Miniaturized Substrate Integrated Waveguide Interdigital Capacitor (SIW-IDC) Antenna

A novel frequency reconfigurable substrate integrated waveguide-interdigital capacitor (SIW-IDC) antenna is presented. The antenna is designed based on a composite right/left-handed (CRLH) resonator, which is realized by the SIW-IDC. Thanks to CRLH characteristics, the antenna size is reduced. Since the IDC determines the resonant frequency, a varactor diode is embedded on the interdigital slot of the short-ended SIW. Its zeroth-order resonance (ZOR) frequency is varied from 4.13 GHz to 4.50 GHz by changing the bias voltage from 0 V to 36 V while keeping good impedance matching better than 15 dB. The radiation performance is numerically and experimentally investigated. Very good agreements between the simulated and measured S-parameters and radiation patterns are observed.