Novel substrate integrated waveguide (SIW)-based power amplifier using SIW-based filter to suppress up to the fourth harmonic

In this paper, a novel 10W substrate integrated waveguide (SIW)-based GaN HEMT power amplifier (PA) using SIW-based filter in both input and output matching networks to suppress up to the 4^th harmonic of 2.14 GHz is analyzed, fabricated, and tested. By connecting two SIW-based stubs with one microstrip-based stub, applying the cutoff frequency characteristic of post-wall waveguide structure, the SIW-based filter which can suppress up to the 4^th harmonic of 2.14 GHz is achieved. With measured result, the insertion loss of the 2^nd, 3^rd, and 4^th harmonics of 2.16 GHz is better than 33 dB, 15 dB, and 20 dB, respectively. Using this proposed SIW-based filter in both input and output matching networks to suppress harmonic components, one SIW-based PA designed at 2.14 GHz is fabricated and tested. Measured results show that, the maximum power added efficiency (PAE) is 61.4% with output power 39.1 dBm at 2.14GHz. The measured maximum gain is 16.1 dB with output power 33.6 dBm.