Li Lingyun

An InP-based heterodimensional Schottky diode for terahertz detection

We present an InP-based heterodimensional Schottky diode (HDSD), which has so far never been reported in the literature. Compared to a GaAs-based HDSD, the InP-based HDSD is expected to have better high frequency performance and operational conditions resulting from its higher mobility and concentration of 2D electron gas (2DEG) as well as its smaller Schottky barrier height. The cutoff frequency of the InP-based HDSD obtained by the AC measurement is more than 500 GHz, which shows its potential application in terahertz detection.

A CMOS variable gain LNA for UWB receivers

A CMOS variable gain low noise amplifier (LNA) is presented for 4.2-4.8 GHz ultra-wideband appli- cation in accordance with Chinese standard. The design method for the wideband input matching is presented and the low noise performance of the LNA is illustrated. A three-bit digital programmable gain control circuit is ex- ploited to achieve variable gain. The design was implemented in 0.13- m RF CMOS process, and the die occupies an area of 0.9 mm 2 with ESD pads. Totally the circuit draws 18 mA DC current from 1.2 V DC supply, the LNA exhibits minimum noise figure of 2.3 dB, S.1;1/ less than -9 dB and S.2;2/ less than -10 dB. The maximum and the minimum power gains are 28.5 dB and 16 dB respectively. The tuning step of the gain is about 4 dB with four steps in all. Also the input 1 dB compression point is -10 dBm and input third order intercept point (IIP3) is -2 dBm.