Compact Antenna Using Finger-Connected Interdigital Capacitor-Based Composite Right/Left-Handed Transmission-Line Unit Cell

Abstract

A compact antenna using a novel finger-connected interdigital capacitor (FC-IDC)-based composite right/left-handed transmission-line (CRLH-TL) unit cell is presented. First, the characteristics of the proposed CRLH-TL are investigated. Compared with the conventional IDC-based CRLH-TL unit cell, the proposed one has a lower $-1\text{st}$ -order resonant mode. Then, an antenna using the proposed CRLH-TL unit cell is designed, fabricated, and measured. By using the conventional IDC-based CRLH-TL unit cell and the microstrip patch, another two antennas are also designed, fabricated, and measured for comparison. The measured results show that the antenna using a CRLH-TL unit cell based on FC-IDC achieves 21.98% and 32.81% reductions in operating frequencies compared with the two antennas with the same size. Additionally, the newly designed antenna can also be implemented easily with printed circuit board technology, which makes it very useful in small communication systems.