Hongfei Yao

A 79 GHz sub-harmonic mixer design using a 1 um InP DHBT technology

This paper presents a 79 GHz sub-harmonic mixer (SHM) design based on a self-developed 1 um InP DHBT process. In this design, a low frequency local oscillator (LO) input signal at 39.5 GHz is doubled to W-band and a radio frequency (RF) signal ranging from 80 GHz to 86 GHz is down-converted to the intermediate frequency (IF) band with a best conversion gain around 1 dB at 83 GHz. As the knowledge of authors, it is the first attempt to implement an InP DHBT based SHM with a LO doubler in W-band. Due to lacking of available RF sources, the testing is realized with one port of an output power fixed Vector Network Analyzer enhanced by a frequency up-conversion module.

W-band MMIC amplifiers based on 50-nm dual-gate InP HEMT

Two MMIC amplifiers have been developed in coplanar technology using 50-nm InAlAs/InGaAs HEMTs. The first is a sing-stage amplifier which used balanced double-stub matching networks for both input and output impedances matching. Measured gain is 8.2 dB @ 81.3 GHz, and the 3-dB bandwidth is at least 13.7 GHz. The second is a two-stage common-source power amplifier. A “#” type distributed transmission line networks has been developed and applied to inter-stage and output stage matching networks. This technique propose a new and efficient approach for impedance matching between transistors where DC blocking and separate bias supplies to the active devices are required. Measured gain is 10.1 dB @ 84 GHz and the 3-dB bandwidth is 14.7 GHz. The saturated power is 11.6 dBm @ 85 GHz, 3.6 dB higher than the above-mentioned single-HEMT amplifier. Measured data are in agreement with the simulation results.

A W-band two-stage cascode amplifier with gain of 25.7 dB

A W-band two-stage amplifier MMIC has been developed using a fully passivated 2 ? 20 ?m gate-width and 0.15 ?m gate-length InP-based high electron mobility transistor (HEMT) technology. The two-stage amplifier has been realized in combination with a coplanar waveguide technique and cascode topology, thus leading to a compact chip-size of 1.85 ? 0.932 mm2 and an excellent small-signal gain of 25.7 dB at 106 GHz. Additionally, an inter-digital coupling capacitor blocks low-frequency signal, thereby enhancing the stability of the amplifier. The successful design of the two-stage amplifier MMIC indicates that InP HEMT technology has a great potential for W-band applications.

A 20-dB gain W-band InP DHBT power amplifier

A two-stage double heterojunction bipolar transistor (DHBT) power MMIC fabricated in InP technology is realized using coplanar waveguide structure. The output cell unit consists of four parallel cascode fingers. Sixteen fingers are at output stage from which the power is combined. Broad-band, low-loss matching networks lead to high gain and high combining efficiency. The chip area is 1.5×1.7 mm2. Measurements show that small signal gain is above 20 dB over 75.5 GHz ~ 84.5 GHz frequency band. Simulated saturated power is 19.7 dBm @ 89 GHz and the actual output power is to be measured once the W-band power source arrive.

A method for multi-mode stability analysis of power amplifier

A method for multi-mode stability analysis of power amplifier is presented which does not demand strict circuit symmetry. Transformation from n-port signals to n-mode signals is used to provide the oscillating signals “mode” information which allows the circuit designer to find the instability source and to adopt suitable methods for circuit stabilization. The proposed method has been applied to a four-branch combining power amplifier circuit to verify its effectiveness.

X-band 11.7-W, 29-dB gain, 42% PAE three-stage pHEMT MMIC power amplifier

This paper presents an X-band high gain and high power three-stage PHEMT monolithic microwave integrated circuit (MMIC) power amplifier (PA). Based on 0.15-μm GaAs power PHEMT technology, this PA is fabricated on a 2-mil thick wafer. While operating under 7.2 V and 3300 mA dc bias condition, the characteristics of 29.2-dB small signal gain, 11.7-W output power, and 42.2% power added efficiency at 9.2 GHz can be achieved.

An 89 GHz single-balanced mixer design in 1 um InP DHBT technology

This paper demonstrates an active single-balanced mixer with InP double heterojunction bipolar transistor (DHBT) process for direct down-conversion system at 89 GHz. Authors use Coplanar Waveguide (CPW) as on-chip transmission line and tune an on-chip CPW balun to allocate LO signal to the switch cell. Benefiting from its balanced structure, this mixer shows a LO port to RF port isolation above 20 dB in all W-band. Its conversion gain is up to 3 dB with a 3 dB RF bandwidth more than 10 GHz. With a 10 dBm LO signal, the RF input 1 dB compression point is higher than -4 dBm around 89 GHz. This mixer consumes 340 mW power with a +4 V supply. All wafers have been thinned to 100 um before measurements.

Compact, broadband waveguide-to-CPWG transition operating around 300 GHz

This letter presents a broadband monolithically integrated waveguide transition module designed for operating around 300 GHz. This transition module employs waveguide WR2.8 and utilizes dipole-based transitions from waveguide to CPWG. The dipole-based transition is designed and fabricated using InP terahertz monolithic integrated circuit (TMIC) technology, so as to be directly integrated monolithically on the TMIC chip, e.g. amplifier, instead of using bond-wires. The measured results show that the insertion loss of this transition is less than 1.5 dB from 285 to 309 GHz, and return loss is better than -9 dB in the whole operation frequency band (270-330 GHz). Moreover, the dipole-based transition has a compact size that is suitable for minimal assembly.

A full W-band low noise amplifier module for millimeter-wave applications

A full W-band low noise amplifier (LNA) module is designed and fabricated. A broadband transition is introduced in this module. The proposed transition is designed,optimized based on the results from numerical simulations. The results show that 1 dB bandwidth of the transition ranges from 61 to 117 GHz. For the purpose of verification,two transitions in back-to-back connection are measured. The results show that transmission loss is only about 0.9-1.7 dB. This transition is used to interface integrated circuits to waveguide components. The characteristic of the LNA module is measured after assembly. It exhibits a broad bandwidth of 75 to 110 GHz,and has a small signal gain above 21 dB. The noise figure is lower than 5.2 dB throughout the entire W-band (below 3 dB from 89 to 95 GHz) at room temperature. The proposed LNA module exhibits potential for millimeter wave applications due to its high small signal gain,low noise,and low DC power consumption.

A method for loop-circuit stability analysis

A method for loop circuit stability analysis is introduced through investigating its closed-loop admittance and open-loop impedance. This method has wider adaptability and less limitation than the traditional approach which uses open-loop power-wave transfer function. A 6-GHz HBT oscillator is designed to verify this method. The measurement result shows the effeteness of the proposed method while the traditional method fails.