A New Method to Extract Gate Bias-Dependent Parasitic Resistances in GaAs pHEMTs

Ruirui Dang,Lijie Yang,Zhiwei Xu,Chunyi Song,Zhihao Lv

doi:10.3390/electronics8030266

Ruirui Dang, Lijie Yang + Show 3 more

Open Access

https://doi.org/10.3390/electronics8030266

Copy DOI

Journal: Electronics	Publication Date: Feb 28, 2019
Citations: 1	License type: CC BY 4.0

Affiliation: Zhejiang Ocean University, Zhejiang University

Abstract

Accurate large signal GaAs pHEMT models are essential for devices’ performance analysis and microwave circuit design. This, in turn, mandates precise small signal models. However, the accuracy of small signal models strongly depends on reliable parasitic parameter extraction of GaAs pHEMT, which also greatly influences the extraction of intrinsic elements. Specifically, the parasitic source and drain resistances, R s and R d , are gate bias-dependent, due to the two-dimensional charge variations. In this paper, we propose a new method to extract R s and R d directly from S-parameter measurements of the device under test (DUT), which save excessive measurements and complicated parameter extraction. We have validated the proposed method in both simulation and on-wafer measurement, which achieves better accuracy than the existing state-of-the-art in a frequency range of 0.5–40 GHz. Furthermore, we develop a GaAs pHEMT power amplifier (PA) to further validate the developed model. The measurement results of the PA at 9–15 GHz agree with the simulation results using the proposed model.

Highlights

Compared with the widely-used 4G mobile communication, 5G has obvious advantages in large-scale antenna arrays, resource utilization, transmission rate, and spectrum utilization.The capacity of 5G is 1000-times that of 4G, and the peak rate can reach 10 Gbps
In order to overcome the disadvantages of poor penetration ability and small coverage due to high frequency in 5G communication, a radio-frequency (RF) power amplifier must deliver high efficiency and linearity. 5G power amplifiers (PAs) used in microcell and macrocells need to provide high Pout, which can be realized by GaAs or GaN [1]
The measurement results of the PA at 9–15 GHz agree well with the simulation results of the proposed method, which indicates the accuracy of the model and the effectiveness of the proposed extract method

Summary

Introduction

Compared with the widely-used 4G mobile communication, 5G has obvious advantages in large-scale antenna arrays, resource utilization, transmission rate, and spectrum utilization. This method is based on a common assumption, that the gate-to-source and gate-to-drain depletion-layer capacitances are equal for a symmetrical device structure in strong inversion. This assumption is not appropriate for pHEMTs due to the pHEMT devices’ asymmetry [7,8]. In order to save excessive measurements and complicated parameter optimization, we propose a new method to determine Rs and Rd. The method utilizes desired device operation in strong inversion and attains on-wafer S-parameter measurements to derive Rs and Rd. The proposed method is verified in both simulation and on-wafer measurement, which achieves better accuracy than the existing state-of-the-art in a frequency range of 0.5–40 GHz. we develop a GaAs pHEMT.

Modeling Rs and Rd

Measurements

Findings

Conclusions