Miniaturized Radio Repeater for Enhanced Wireless Connectivity of Ad-Hoc Networks

A new concept for development of a high-gain and miniaturized radio repeater is presented in this paper. The proposed system utilizes a small array of low-profile miniaturized planar antennas with vertically polarized radiation pattern as well as a modified ring hybrid coupler as the array power distribution circuit and a low-power high-gain amplifier chain. In this configuration, a small receiving antenna is placed between a pair of transmit antenna array, which are fed 180° out of phase. The transmit array creates a null-plane where the receive antenna is placed, and this way an isolation value between the transmit and receive antennas in excess of 50 dB is achieved, while the shortest distance between the transmit and receive antennas is less than 0.16λ₀. The proposed repeater has a small form factor and occupies a small volume (0.22λ₀² × 0.03λ₀). A prototype of the miniaturized radio repeater is fabricated and measured to verify the system performance. A radar cross section of the repeater is measured for evaluating the overall system gain and its bandwidth. It is shown that an amplifier chain with a gain of 50 dB can be inserted between the transmit and receive antennas, which results in the measured repeater RCS of 21.3 dBsm.