Design of a Compact and Minimalistic Intermediate Phase Shifting Feed Network for Ka-Band Electrical Beam Steering

Intermediate phase shifting is a footprint- and cost-reduction technique for reconfigurable feed networks. These feed networks are utilized in antenna arrays to perform electrical beam steering. In intermediate phase shifting, a phase shifter is shared between two adjacent antennas. Conventionally, antennas only have individual phase shifters. With shared phase shifters, we reduce the number of components and the footprint by 25%. Consequently, this decreases the price and enables designs at millimeter-wave frequencies where space is limited due to frequency-dependent antenna spacing. This intermediate phase shifting is demonstrated by designing a reconfigurable feed network for the Ka-band that generates a continuous phase shift profile for beam steering. Due to the use of varactors and a novel biasing method, it does not require expensive beamformer integrated chips or lumped components for biasing. The feed network is combined with a 4 x 4 antenna array to demonstrate its beam-steering capabilities. The result is a high-density and minimalistic design that fits in a small volume of 25.6 x 25.6 x 0.95 mm3. With this small antenna array, the main beam is steered at +/- 40 circle broadside, providing full 1D and restricted 2D steering. It is a potential candidate for wireless sensor and mobile networks.