The Ranatec RI 3101 Butler Matrix is a beamforming network which typically is used to feed a phased array of antenna elements. It controls the directions of a beam, or beams, of a radio transmission. The beam direction is controlled by switching power to the desired beam port.

The RI 3101 Butler Matrix is designed for wireless test applications using microstrip technology. The design and optimization was used based on computer simulations using ADS and HFSS. The hybrid couplers, cross-couplers, and the phase shifters are optimized one by one to get the best performances.

An important feature that makes RI 3101 Butler Matrix attractive is the speed over mechanical scanning systems. In transmit mode it delivers the full power of the transmitter to the beam, and in receive mode it collects the signal from each of the beam directions with the full gain of the antenna array.

Since the Ranatec Butler Matrix 8×8 is both reciprocal and passive, it can be used for both transceiver and receive applications.