With the rapid development of Internet of things (IoT), Radio Frequency Identification (RFID) has become one of the most significant information technologies in the 21st century. However, more and more privacy threats and security flaws have been emerging in various vital RFID systems. Traditional RFID systems only focus attention on foundational implementation, which lacks privacy protection and effective identity authentication. To solve the privacy protection problem this paper proposes a privacy protection method with a Privacy Enhancement Model for RFID (PEM4RFID). PEM4RFID utilizes a “2+2” identity authentication mechanism, which includes a Two-Factor Authentication Protocol (TFAP) based on “two-way authentication”. Our TFAP employs “hardware information + AES-ECC encryption”, while the ”“two-way authentication” is based on improved Combined Public Key (CPK). Case study shows that our proposed PEM4RFID has characteristics of untraceability and nonrepeatability of instructions, which realizes a good trade-off between privacy and security in RFID systems.

We have developed a power amplifier IC for Bluetooth Class 1 operating at single low voltage of 1.8 V for both control and drain voltages. We can realize it due to fully enhancement-mode hetero-junction FETs utilizing a re-grown p +-GaAs gate technology. The power amplifier is a highly compact design as a small package of 1.5 mm1.5 mm0.4 mm with fully integrated gain control and shutdown functions. An impressive power added efficiency of 52% at an output power of 20 dBm is achieved with an associated gain of 22 dB. Also, sufficiently low leakage current of 0.25 µA at 27 is exhibited, which is comparable to conventional HBT power amplifiers.

Based on fluoride-based plasma treatment of the gate region in AlGaN/GaN HEMTs and post-gate rapid thermal annealing (RTA), enhancement mode (E-mode) AlGaN/GaN HEMTs with low on-resistance and low knee-voltage were fabricated. The fabricated E-mode AlGaN/GaN HEMT with 1 µm-long gate exhibits a threshold voltage of 0.9 V, a knee-voltage of 2.2 V, a maximum drain current density of 310 mA/mm, a peak gm of 148 mS/mm, a current gain cutoff frequency fT of 10.1 GHz and a maximum oscillation frequency fmax of 34.3 GHz. In addition, the fluoride-based plasma treatment was also found to be effective in lowering the gate leakage current, in both forward and reverse bias. Two orders of magnitude reducation in gate leakage current was observed in the fabricated E-mode HEMTs compared to the conventional D-mode HEMTs without fluoride-based plasma treatment.