On direct matching and efficiency improvements for integrated array antennas

Abstract

The goal of this design study is to determine the insertion-loss associated with a sequence of impedance-matching networks. These results are compared to the performance of direct integration of PA/antenna. In high-frequency, ≥ 20GHz, co-design of PA/antenna has as an important goal to remove any matching networks between the antenna and power amplifier by e.g. antenna shaping both to reduce the physical size and to improve the power added efficiency of the radio-front end. We determine the insertion-loss for matching a 2W GaN RF Transistor TGF2942 working in Class-A to a given real-valued load. This type of reference can serve as a benchmark to compare co-designed antenna performance. We also determine changes in power added efficiency and insertion-loss associated with changes in the physical size of a sequence of differently sized matching-network. The results are examined with respect to the electrical size, choice of material (dielectric attenuation), and given $Z_{\mathbf{ant}}$ & $Z_{\mathbf{opt}}$. In the reference case, we observe that direct matching may improve the power added efficiency by 10% for a 5% frequency bandwidth and by 6% at the center frequency.