engleski

Compact UHF amateur radio quad antenna for indoor use

Due to the confined space in which they are typically used, directional ultra– highfrequency (UHF) antennas for indoor use should be particularly compact. Also, due to the frequent need to manually direct (rotate) the antenna, it must be relatively light with good mechanical characteristics. By simultaneously considering the compactness of various types of antennas, weight, electrical, electromagnetic, mechanical, and radiation properties of antennas, several types of antennas are particularly suitable for directional UHF amateur radio antennas for indoor use. In this sense, various types of quad antennas stand out. Despite the fact that Quad antennas have excellent performance and electromagnetic properties, because of their complicated and slow construction, they are not popular among radio amateurs. This article presents a new idea in the selection of materials for the construction and construction solution of Quad antennas for indoor use. The presented construction solution simultaneously ensures a simple construction but with significantly reinforced mechanical characteristics compared to the typical constructions of Quad antennas. This article presents the design of compact UHF Quad antennas suitable for indoor applications. The presented antennas are dual stacked Quad antennas. Impedance matching was achieved by coaxial cables. The antennas are built for the frequency of 446 MHz, the so–called personal mobile radio (PMR). Both antennas were tested for mechanical stress typical for their use such us moving and rotating the antennas. After prolonged use, no damage, deformation, or weakening of the joints was observed. Numerical calculations and optimizations of the presented antennas were performed using 4nec2 software. The measured voltage standing wave ratio (VSWR) of the presented antennas is below 1.5.

amateur radio ; compact antenna ; quad antenna ; pmr radio ; stacked antenna

This paper was presented at IIZS 2022 – The XII International Conference on Industrial Engineering and Environmental Protection, organized by Department of Mechanical Engineering and Department of Environmental Protection of the Technical Faculty “Mihajlo Pupin” Zrenjanin, from the University of Novi Sad.