Highly Integrated PA-PIFA With a Wide Frequency Tuning Range

This letter presents a highly integrated power amplifier (PA) antenna with the capability of frequency tuning. A planar inverted-F antenna (PIFA) is used to directly match the PA transistor. This mitigates the lossy output matching network in the PA-integrated antenna (PAIA). In order to achieve a wide frequency tuning range, a combination of capacitors is loaded at the PIFA to control the antenna input impedances so that matching can be maintained with frequency tuning. The antenna analysis and design procedure of the tunable PAIA are detailed. For verification, a prototype is designed, fabricated, and measured. The experimental results show that the frequency tuning range of the proposed PAIA covers from 2 to 4 GHz. Over this frequency tuning range, the effective isotropic radiation power and power-added efficiency are higher than 40.5 dBm and 60% at the input power of 26.5 dBm, respectively.