Design of 340 GHz 2× and 4× Sub-Harmonic Mixers Using Schottky Barrier Diodes in Silicon-Based Technology

Chao Liu,Yong-Zhong Xiong,Xiang Li,Yihu Li,Haitao Liu,Qiang Li

doi:10.3390/mi6050592

Chao Liu, Yong-Zhong Xiong + Show 4 more

Open Access

https://doi.org/10.3390/mi6050592

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Abstract

This paper presents the design of terahertz 2× and 4× sub-harmonic down-mixers using Schottky Barrier Diodes fabricated in standard 0.13 μm SiGe BiCMOS technology. The 340 GHz sub-harmonic mixers (SHMs) are designed based on anti-parallel-diode-pairs (APDPs). With the 2nd and 4th harmonic, local oscillator (LO) frequencies of 170 GHz and 85 GHz are used to pump the two 340 GHz SHMs. With LO power of 7 dBm, the 2× SHM exhibits a conversion loss of 34.5–37 dB in the lower band (320–340 GHz) and 35.5–41 dB in the upper band (340–360 GHz); with LO power of 9 dBm, the 4× SHM exhibits a conversion loss of 39–43 dB in the lower band (320–340 GHz) and 40–48 dB in the upper band (340–360 GHz). The measured input 1-dB conversion gain compression point for the 2× and 4× SHMs are −8 dBm and −10 dBm at 325 GHz, respectively. The simulated LO-IF (intermediate frequency) isolation of the 2× SHM is 21.5 dB, and the measured LO-IF isolation of the 4× SHM is 32 dB. The chip areas of the 2× and 4× SHMs are 330 μm × 580 μm and 550 μm × 610 μm, respectively, including the testing pads.

Highlights

In the design of millimeter wave or terahertz transceiver, the generation of the local oscillator (LO) signal with high power is rather difficult
The simulation is done with extensive EM simulations by High Frequency Structure Simulator (HFSS) along with the Schottky barrier diodes (SBDs) model in Advanced Design Systems (ADS) provided by the Process Design Kit (PDK)
For the 4× sub-harmonic mixers (SHMs), the measured lower band (320–340 GHz) conversion loss is 39–43 dB, which is in good agreement with the simulated result; but the measured conversion loss for the upper band (340–360 GHz) is 40–48 dB, which is much larger than the simulated results

Summary

Introduction

In the design of millimeter wave or terahertz transceiver, the generation of the LO signal with high power is rather difficult. Using sub-harmonic mixers is the alternative solution by reducing the LO frequency by half or even higher order. The topology of anti-parallel-diode-pair (APDP) has its advantages of no Direct Current (DC) power consumption, suppressing all even harmonics of the LO signal, and with compact structure; it becomes a popular scheme to realize a sub-harmonic mixer (SHM). Schottky barrier diodes (SBDs) have been widely used to implement a high frequency APDP due to their high switching speed and low voltage drop [1]. SHM utilizing SBDs in silicon-based technologies for terahertz applications has seldom been reported. We present the design of the 340 GHz 2× and 4× sub-harmonic down-mixers using. Schottky barrier diodes fabricated in a standard 0.13 μm SiGe BiCMOS technology

Schottky Barrier Diode Structurre

A I S exp

Circuit Design

Measurement and Discussion

Conclusions