High-Frequency Signal Generator using Cascaded Frequency Multiplier

This paper presents a method for increasing the operating frequency range of sub-6 GHz transmitter to millimetre wave (mm-wave) using two cascaded doublers. The usage such up-conversion approach is constrained since applying first doubler’s generated harmonics second doubler mm-wave signal creation, results in severe distortions and bandwidth expansion transmitted signal, limiting use method. We have proposed combined gain phase retarder physically inspired feed-forward neural network (CFFNN) based digital predistortion mitigate distortions. A comparative study networks (FFNN) CFFNN has been carried out establish as significant less complex model effective DPD quadrupler. For proof concept, we experimentally validated this Long-Term Evolution (LTE) 20 MHZ (64-QAM) at 24 band commercially available multipliers. measurement show reduced approximately 11-12 times, adjacent channel power ratio (ACPR) around -45.1 dBc error vector magnitude (EVM) 3.07% achieved.