An External Calibration Scheme for DBF Antenna Arrays

A novel calibration scheme is presented that is especially suited for complex digital beamforming (DBF) antenna arrays at millimeter-wave frequencies. Calibration data is extracted by sampling the field of each radiator at certain locations near the array by fixed probe antennas. A scalable calibration model for evaluation of the measured data is described. First tests are performed on a small passive array representing a unit cell of larger arrays. The calibration scheme is subsequently applied to and tested on a 64 element DBF transmit antenna array.

I. Introduction

Future mobile satellite communication systems are driven by requirements such as large bandwidth and high flexibility. Planar antenna arrays featuring digital beamforming at Ka-band frequencies show the highest potential for advanced communication terminals [1]–[4]. Specialized architectures suitable for large-scale implementation are investigated within the frame of the project SANTANA (Smart ANTennA termiNAl) [2]–[4]. The common characteristics of the various architectures are modular array assembly and split transmit/receive functions. Parallel studies cover array calibration and other system aspects [5], [6].