Coupled line triangular microstrip loop resonator antenna

Abstract

An isosceles triangular microstrip loop antenna is presented. The resonator is fed by two quarter wavelengths parallel-coupled sections. The proposed feed arrangement is a parallel-coupled microstrip lines with the coupling taking place over an electrical length. The edge-coupled two quarter wavelengths parallel-coupled microstrip line sections are combined capacitively. Each end of the feed arrangement is terminated in 50 Ω impedance. One 50 Ω end of the proposed feed is connected to the source similar to that of the microstrip feed line, while the second end is connected to the resonator itself. Similar antenna structure was designed and fed, first by a conventional microstrip feed line, inset feed, and inset coupled, and finally with a quarter wavelengths microstrip feed. This is done to further identify the specific advantages of the proposed feed structure. The peculiarities of the antenna with its proposed feed network are discussed as well as a theoretical explanation of the concept of the coupled line feed to wit its gain and bandwidth enhancement. It was observed that the measured gain of the proposed antenna is 8.38 dBi with a side lobe level of –10.8 dB, and an antenna aperture size of 30 mm × 16 mm.

Keywords:

• coupled line
• impedance match
• isosceles
• loop
• triangular patch antenna