Measurements and Validation of Integrated and Active Antenna Arrays

Licentiate thesis, 2026

Active integrated antennas (AIAs), including antenna-in-package (AiP) and antenna-on-chip (AoC) implementations, tightly couple radiating structures with active circuitry and therefore lack accessible antenna ports. While this integration improves efficiency, compactness, and beamforming capability at millimeter-wave and sub-terahertz frequencies, it fundamentally complicates measurement and validation. Traditional characterization methods are often infeasible due to the absence of accessible antenna ports, and conventional over-the-air (OTA) techniques primarily provide field-based observables such as radiation patterns and radiated power, offering limited direct insight into terminal electrical quantities.

This licentiate thesis addresses the challenge of extracting electrically meaningful information from integrated antenna arrays without direct RF access. A scalable backscattering-based OTA measurement framework is developed, in which controlled load modulation at the antenna ports enables reconstruction of input impedance and realized gain from remotely measured scattering responses. The methodology is extended from single-element demonstrations to array-level characterization and reconfigurable intelligent surfaces (RIS), establishing a generalized measurement architecture suitable for integrated apertures with embedded switching capabilities.

In parallel, electronically controlled load-pull techniques are investigated as a complementary tool for validating active RF devices under realistic antenna-imposed loading conditions. A compact, self-contained load-pull measurement platform is implemented to emulate dynamic load environments and study device behavior in integrated contexts. Together, these contributions advance the measurement and validation of active integrated antenna systems by bridging field-based OTA observations and terminal-level electrical characterization, enabling more reliable system-level verification of highly integrated millimeter-wave architectures.