A Comparative Analysis of Antenna Performance in SDR-Based Congested Spectral Environments

Dynamic spectrum access (DSA) and cognitive radio (CR) systems, built on software-defined radio (SDR) platforms, enable adaptive spectrum use and reconfiguration. Reconfigurable and filtering antennas play a key role in DSA by reducing the need for extra filtering circuits and rejecting out-of-band (OOB) signals. However, a comprehensive analysis of their impact on SDR-based DSA system performance is yet to be conducted. This work introduces a novel SDR-based testbed emulating frequency-variant interference to evaluate broadband, reconfigurable, and filtering antennas by measuring received interference power and signal-to-interference-plus-noise ratio (SINR) in congested environments. The filtenna reduces received interference power by 3.15% and achieves a 248:1 peak-to-band edge ratio, a measure of performance when an interferer is located at the edge of the band. When comparing system-level performance between antenna types, the horn antenna predictably achieves the highest peak SINR. In contrast, the filtenna exhibits less OOB degradation, demonstrating its potential to enhance performance in congested spectrum scenarios.