Grid reflector with four bow-tie phased array feed

Image of the Grid reflector with four bow-tie phased array feed.

This grid reflector is a popular, low cost reception antenna for terrestrial television signals in the UHF band. The antenna may be easier to mount and is less obtrusive than the other low cost reception antennas such as Yagi-Uda and LPDA-type antennas.

Typical 3D gain patterns at 0.8 of the centre frequency, at the centre frequency and at 1.2 of the centre frequency.

The array of wire bow-tie antennas provides a fairly simple, yet wideband array with an integrated feed structure. This antenna requires a balun when feeding the structure with a coaxial cable or other unbalanced transmission line type. The balun is often designed to also provide impedance matching. For example, in TV applications, the balun provides an impedance transformation from 300 Ohm to 75 Ohm.

By placing a planar reflector behind the bowtie array, a directional radiation pattern is achieved. The wire construction of the grid reflector makes the antenna light-weight and practical at lower frequencies. While the bowtie array feed provides acceptable input reflection performance over a 2:1 band, the usable bandwidth is dictated by the pattern stability - which is limited to approximately 1.55:1.

VSWR performance of the antenna in a 300 Ohm system.