Shao-Wei Lin

A High-Linearity Single-Pole-Double-Throw Pseudomorphic HEMT Switch Based on Tunable Field-Plate Voltage Technology

A high-isolation high-linearity GaAs pseudomorphic high-electron mobility transistor single-pole-double-throw microwave switch was developed using a tunable field-plate (FP) bias voltage technology. In this paper, a piece of FP metal was deposited between 0.15-mum-long gate and drain terminals. An extra FP-induced depletion region was generated to suppress the harmonics of switching associated with OFF-state operation. When switching into the ON-state, the FP switch is associated with an insertion loss similar to that of the standard switch below 6 GHz. However, the isolation performance can be enhanced by 10 dB using an FP technology, which reduces the OFF-state capacitance that is produced by the extra FP-induced depletion region. The FP provides an additional mechanism to suppress the power of the second- and third-order harmonics in the OFF-state with slight ON-state insertion-loss degradation.

Comprehensive study of gate-terminated and source-terminated field-plate 0.13 µm NMOS transistors

This study systematically investigated microwave noise, power and linearity characteristics of field-plate (FP) 0.13 µm CMOS transistors in which the field-plate metal is connected to the gate terminal and the source terminal. The gate-terminated FP NMOS (FP-G NMOS) provided the best noise figure (NF) at 6 GHz compared with standard devices and the source-terminated FP device (FP-S NMOS) as the lowest gate resistance (Rg) was obtained by this structure. By adopting the field-plate metal in NMOS, both FP-S and FP-G devices achieved higher current density at high gate bias voltages. Moreover, these two devices also had higher efficiency under high drain-to-source voltages at the high input power swing. The third-order inter-modulation product (IM3) is −39.4 dBm for FP-S NMOS at Pin of −20 dBm; the corresponding values for FP-G and standard devices are −34.9 dBm and −37.3 dBm, respectively. Experimental results indicate that the FP-G architecture is suitable for low noise applications and FP-S is suitable for high power and high linearity operation.

A Study of Gate/Source-terminated Field-Plate NMOS Transistors and Its application in Switch Design

We have systematically studied the microwave noise, power, and linearity characteristics of field-plate (FP) 0.13-mum CMOS transistors in which the field-plate are separately connected to the gate and source terminals. The gate-terminated FP NMOS (FP-G NMOS) provided the best minimum noise figure (NFmin) at 6 GHz compared to standard device and source- terminated FP device (FP-S NMOS) owing to the lowest gate resistance (Rg) can be obtained in this structure. By adopting FP metal in NMOS, both FP-S and FP-G devices achieved higher current density at high gate bias voltages; besides, they also demonstrated higher efficiency under high drain-to-source voltages at high input power swing. The third-order inter- modulation product (IM3) is -39.4 dB for FP-S NMOS for Pin=-20 dBm; the corresponding values for FP-G and standard devices are -34.9 and -37.3 dB, respectively. These experimental results indicated that the FP-G architecture is suitable for low noise applications and FP-S is more effective at high power and high linearity operation. Finally, a 24 GHz T/R switch was designed and fabricated by using FP-S NMOSs for achieving good ability of isolation and harmonics rejection ratio.

A direct conversion WiMAX RF receiver front-end in GaAs 0.5µm ED-mode pHEMT technology

This paper presents a direct conversion RF receiver front-end supporting the WiMAX (802.16e) standard. The front-end is implemented in 0.5 um GaAs ED-Mode pHEMT technology and designed using the ADS software. It shows how the design flow can be accelerated starting from the standard specifications and going down to schematics. All this is accompanied by test benches to extract the relevant metrics. This front-end provides a total gain of 13 dB.

High performance 0.15 µm gate pHEMT V-band tripler using compact microstrip resonant cell (CMRC) technique

A V -band current reuse frequency tripler is developed in 0.15um pseudomorphic high electron mobility transistor (pHEMT) technology. This tripler combines the compact microstrip resonant cell (CMRC) topology for suppress unwanted harmonic and current-reuse technique to improve the conversion gain. At 60 GHz, the tripler achieved as minimum conversion gain of −16.6 dB at an input power of 8 dBm; the suppressions of the fundamental and second harmonic frequencies were 22 dB and 27 dB, respectively.

A High Isolation 0.15μm Depletion-Mode pHEMT SPDT Switch Using Field-Plate Technology

A high isolation GaAs microwave switch has been successfully developed using field-plate technology, which is effective to improve the isolation. The developed wideband SPDT switch shows a greater than 40 dB isolation before 10 GHz and also achieves good performance at higher frequency. A GaAs-based pseudomorphic high electron mobility transistors (pHEMTs) in which the field-plate (FP) metal is supplied with various biases was developed and evaluated experimentally to determine their dc and rf performance. Owing to the depth modulation of the field-plate-induced depletion region at various field-plate biases, the intrinsic devices were influenced by the tunable VFP. This technique is easy to apply, based on standard p HEMT fabrication.