Phased Array Calibration: Overcoming Productization Challenges in CMOS Analog Beamforming Arrays

Phased arrays are a key component in most mm-wave and higher frequency wireless systems. Although the theory of beamforming and phased arrays is well established, the increasing number of elements in the antenna arrays, smaller process-nodes, and the extremely high cost of mm-wave equipment have imposed a multitude of challenges in productizing modern beamforming ICs. Proper calibration with shorter calibration times is highly desired in today’s commercial beamforming RFICs for obtaining optimal performance. This tutorial will discuss the post-fabrication impairments in analog CMOS phased arrays, as well as calibration methodologies adopted for gain, phase and TX power calibration, with an emphasis on fast and non-over-the-air cost-effective measurement methodologies.