Design Challenges and Solutions for Characterizing Mutual Coupling Coefficients in PCB-Based Ka-Band Dual-Polarized Wide-Scan Phased Arrays

Paper in proceeding, 2026

A scalable measurement setup for PCB-based, wide-scanning phased arrays operating in the SATCOM Ka-band (27.5-31 GHz) is designed. This setup addresses the critical challenges of dense element spacing in dual-polarization configurations as well as the non-ideal performance of commercial surface-mount device (SMD) resistors at millimeter-wave frequencies. The measurement setup uses SMD connectors and resistors, eliminating the need for additional fixtures and/or PCB conductor layers. The footprint required for the connector transition is minimized by shaping the connector pad, reducing the number of pad-grounding vias needed, and increasing the flexibility in connector pad placement. Miniaturized terminations using SMD resistors are designed by co-simulating transmission lines, grounding vias and resistor equivalent models. The designed terminations and transition are used in the fabrication of phased array prototypes. Test boards for the transition and terminations are fabricated and their S-parameters measured. The measurement results validate the repeatable performance of the designed components.