Characteristics of High-Gain Wideband Ring Loop Antenna and its Application

Abstract

Digital terrestrial broadcasting services are in the Japanese UHF band of 470 to 770 MHz. The bandwidth of the UHF-TV channel is 6 MHz. In this paper we investigate the ring loop antenna for the UHF digital terrestrial broadcasting. The characteristics of the linear ring loop and circular ring loop antenna are calculated by NEC-WIN Pro. We evaluate the characteristics of these antennas in the Japanese UHF-TV broadcasting band (470MHz770MHz). A broadband antenna consisting of the ring loop antenna is presented for the digital terrestrial broadcasting. A ring loop antenna is excited by a simple and low-cost feeder system. The broadband input impedance and the high gain are obtained in the calculation and the measurement. The input impedance became 50Ωand wideband characteristics were obtained in the simple power supply construction. Then the high-gain and wideband characteristics were obtained with the simple power supply construction. This antenna has sufficient characteristics as the transmitting antenna for digital terrestrial broadcasting stations and repeater stations in the Japanese UHF band. The characteristics of the ring loop antenna were calculated using the moment method proposed by Harrington[1][2], who conducted experiments on this antenna. This antenna examined the ring loop antenna with which circumference length fed in parallel in about full-wavelength of loop antenna element as an antenna for digital terrestrial broadcasting. That is, numerical analysis was performed about conditions for both the directivity of the ring loop antenna of many stages and the impedance characteristic to show the broadband characteristic. It is the ring loop antenna of the structure, which carried out parallel electric feed of all the elements in this antenna, added one reflector element, and was arranged to the vertical form. All number element of the antenna was consisted of sum total of 5-elements of director element of 3-elements, radiator element, and compound reflector element. This antenna it was the simple structure in order to solve the problem, and the diameter was small, and the miniaturization was possible, and again, it developed ring loop antenna (RLA) for the digital terrestrial broadcasting of which 8