Ferrite Circulator Integrated Phased-Array Antenna Module for Dual-Link Beamforming at Millimeter Frequencies

This paper presents the design of dual-port subarray modularization integrating a three-port circulator, realized by using substrate integrated waveguide (SIW) technology, and a subarray of antenna elements for dual uplink and downlink beamforming. In particular, a 2 × 2 element module is implemented and fabricated on a standard printed circuit board substrate to demonstrate its radiation characteristics and operational mechanism. In this design, the SIW structure is used to reduce the radiation from microstrip lines at millimeter-wave frequencies and avoid contaminating the radiation patterns of subarrays. Greater than 5 dBi suppression has been achieved for good compatibility with the integration of radio frequency devices. The measured results show that the subarray modularization improves the insertion loss and results in an excellent isolation for independent transmitting and receiving beamforming network implementation. Numerical and experimental results are shown to verify the performance of these designs.