J-shaped monopole antenna array as an antenna for terrestrial digital broadcasting at UHF band

To develop compact and thin antennas at UHF-band, a printed J-shaped monopole array antenna was discussed for reception of terrestrial broadcasting TV signals. This antenna consists of a folded J-shaped lambda/4 monopole antenna array fed by a coplanar waveguide. A simple matching circuit consisting of an open-ended slotted line and high impedance step section were installed between the antenna and the ground plane of the coplanar waveguide to reduce reflection from the antenna. From the analyzed and measured results, it was confirmed that the return loss performance guaranteed the specification of the digital terrestrial broadcasting in the frequency ranges from 440 MHz to 770 MHz. The radiation pattern of this antenna array was similar to that of the monopole antenna and the antenna gain was more than -10 dBi. The proposed J-shaped monopole array antenna with the simple matching technique has capability to apply into mobile and indoor terrestrial broadcasting TVs because the antenna size is reasonably small to be constructed in the 1.6 mm-thickness paper phenol substrate with an area of 80 mm times 100 mm.