Compact Antenna Using Novel Finger-Connected Interdigital Capacitor-Based Substrate Integrated Waveguide Cavity

A electrical small antenna using a novel finger-connected interdigital capacitor (FC-IDC), based on composite right/left handed (CRLH) unit cell, is proposed in this paper. The proposed CRLH antenna consists of a thin rectangle substrate integrated waveguide (SIW) cavity with the etched interdigital slot on the top metal surface and two etched slot rings on the bottom metal surface, which is fed by a grounded co-planar waveguide (GCPW). The interdigital slot acts as a series capacitor as well as a radiator leading to a CRLH antenna application. Compared to other conventional CRLH antenna, the proposed one has a lower -1st-order resonant mode. thus, the present design has a smaller electrical size. The results show that the antenna using a novel CRLH-TL unit cell based on FC-IDC achieves 30.5% reductions in operating frequencies compared with the conventional CRLH antennas with the same size. In addition, the novel designed antenna can be easily fabricated by printed circuit board technology, which is of important significance in the miniaturization of communication system.