Design and Fabrication of VHF Band Small Antenna Using Composite Right/Left-Handed Transmission Lines

Abstract

This paper presents a small VHF antenna using a composite right/left-handed (CRLH) transmission lines. The proposed antennas have 3 and 7 unit cells that consist of interdigital capacitors and shunt spiral inductors. The size of the antenna with 3 unit cells is 0.039λ × 0.025λ × 0.0008λ (72.9 × 47.5 × 1.52 mm3) at 161 MHz and its peak gain is − 33 dBi. To enhance the gain, the antenna with 7 unit cells is fabricated. Its size is 0.089λ × 0.025λ × 0.0008λ (167.2 × 47.5 × 1.52 mm3) at 161.4 MHz and its peak gain is − 26.5 dBi. The radiation pattern of both antennas is omni-directional. The electrical size in kr of each antenna is 0.055 and 0.11, respectively. The effects of frequency characteristic of lumped elements on the impedance matching are discussed.