A matching technique of J-shaped monopole array antenna for terrestrial digital broadcasting reception

For the purpose of developing compact and thin antennas at UHF-band, a monopole array antenna consisting of folded J-shaped λ/4 monopole antennas was devised. And, matching circuits such as an open-ended slot transmission line stub and a high impedance step section were installed to improve the antenna performance. In this paper, to clarify the physical meaning of the matching circuits, a radiation characteristic of the open-ended slotted line was calculated by using the electromagnetic simulator, and besides, an equivalent circuit consisting of the antenna and the matching circuits was considered. According to this result, agreement between the network theory and the full-wave analysis is reasonably satisfactory, and hence the validity of the matching circuits.