Harmonic Cancellation Technique for Ultra-Wideband Filter-Less 5G Transmitter

To support ultra-wideband transmitter, bulky filter banks are required for suppressing the harmonics at the power amplifier output. Therefore this increases the transmitter size as well as cost. This paper proposes a digitally supported harmonic injection scheme to cancel out the modulated harmonics with the provision of frequency reconfigurability and small size. The proposed filter less architecture is realized in a low-cost field-programmable gate array (FPGA) suitable for the fifth generation (5G) remote radio unit/remote radio head. For proof-of-concept, three different frequencies are chosen. The experimental verification reveals a reduction of approximately 29 dBc of second harmonic signal. Moreover with the proposed cancellation algorithm, the harmonic reduced to approximately 55 dBc below the main channel.