A novel, modified small signal behavioral modeling methodology for gallium nitride (GaN) high electron-mobility transistors (HEMTs), based on the support vector regression (SVR) technique, is presented in this paper. Compared with the classic equivalent small-signal circuit model, the proposed model adds an error correction technique, which is developed using SVR techniques. The proposed model maintains accuracy across a broad frequency range, from 1 GHz to 10 GHz. The verification is performed through comparisons with measured multibias S-parameter data performed on an 8 Â 125 μm GaN HEMT device with a 0.25 μm gate feature size. The modified model shows a significant improvement in S-parameter prediction accuracy when compared with the classic equivalent circuit modeling approach.

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DCSK modulation in chaos communication is a robust non-coherent modulation scheme. In this paper, the multiple-access DCSK scheme based on the OVSF code is proposed. Using the multiple-access DCSK scheme in RFID system, a DCSK-RFID system is presented. In the presented DCSK-RFID system, we use the DCSK for tag modulation for its low complexity and the simple receiver of the DCSK scheme is applied in reader part. The tag's BER performance of the proposed DCSK-RFID system is carefully generalized both in theoretic analysis and in simulations. From the simulation results, the theoretical and simulation values match closely with each other. Then, we design an anti-collision MAC protocol based on multi-access DCSK-RFID scheme. We theoretically analyze the throughout in given number of tags. The simulation shows that the proposed algorithm has better throughout than S-Aloha system.