Che Hung Lin

An X-Band High-Power and High-PAE PHEMT MMIC Power Amplifier for Pulse and CW Operation

An X-band high-power and high power added efficiency (PAE), two-stage AlGaAs/InGaAs/GaAs psuedomorphic high electronic mobility transistor (PHEMT) monolithic microwave integrated circuit (MMIC) power amplifier is presented. The amplifier is designed to fully match a 50 Omega input and output impedance. Based on a 0.35 mum gate-length power PHEMT technology, the MMIC is fabricated on a 3 mil thick wafer. Under an 8 V DC bias condition, the characteristics of 17.5 dB small-signal gain, 10 W continuous wave mode saturation output power of 42% PAE, and 12.6 W pulse saturation output power of 52.6% PAE at 9.4 GHz can be achieved.

A 23–37 GHz Miniature MMIC Subharmonic Mixer

A novel configuration of subharmonic mixer using an anti-parallel diode pair is presented for operating over the 23-37 GHz band. The monolithic microwave integrated circuit is implemented by GaAs 0.15 mum PHEMT technology with the compact size of 0.85 times 0.85 mm2. This mixer employs a directional coupler, LC low-pass filter, and a short stub for isolating three ports corresponding to radio frequency (RF), local oscillation (LO) input, and intermediate frequency (IF) output ports. The directional coupler also provides impedance transformation between the diode pair, RF, and LO ports. This makes the subharmonic mixer more compact and flexible. The best conversion loss of the subharmonic mixer is 9.4 dB, and the LO-to-RF and LO-to-IF isolations are better than 22 and 31 dB, respectively.

A 9.1–10.7 GHz 10-W, 40-dB Gain Four-Stage PHEMT MMIC Power Amplifier

This letter presents a compact X-band high gain and high power four-stage AlGaAs/InGaAs/GaAs pseudomorphic high electron mobility transistor (PHEMT) monolithic microwave integrated circuit (MMIC) high power amplifier (PA). This amplifier is designed to fully match a 50-Omega input and output impedance. Based on 0.35-mum gate-length power PHEMT technology, this PA MMIC is fabricated on a 3-mil thick wafer. While operating under 8 V and 2700-mA dc bias condition, the characteristics of 40-dB small-signal gain, a 10-W continuous-wave saturation output power, and 33% power added efficiency at 9.7GHz can be achieved

A Compact Ka-Band Planar Three-Way Power Divider

A Ka-band planar three-way power divider which uses the coupled line instead of the transmission line is proposed to reduce chip size. The proposed planar topology, different from the conventional Wilkinson power divider, is analyzed and can provide not only compact but also dc block characteristics, which are very suitable for monolithic microwave integrated circuit applications. The divider implemented by a pHEMT process shows an insertion loss less than 5.1 dB and an output isolation better than 17 dB. A return loss less than 18 dB and a phase difference of 4.2deg at 30 GHz can be achieved. Finally, good agreements between the simulation and experimental results are shown.

A Variable Conversion Gain Star Mixer for Ka-Band Applications

A variable conversion gain star mixer for Ka-band applications has been presented. This monolithic microwave integrated circuit was implemented on AlGaAs/InGaAs/GaAs pseudomorphic high-electron-mobility transistor process with a chip size of 1.7times1.7 mm2. The mixer is modified from conventional star mixer to apply dc bias. The conversion gain of the mixer, controlled by the voltage of the diodes, could be applied to meet gain compensation requirements in communication systems. From the measured results, the circuit can provide 11.9 dB conversion gain and 9.3 dB gain adjustment by controlling voltage from 0 to 0.7 V at 30 GHz.

A Compact 6.5-W PHEMT MMIC Power Amplifier for Ku-Band Applications

A compact 6.5-W AlGaAs/InGaAs/GaAs PHEMT monolithic microwave integrated circuit (MMIC) power amplifier (PA) for Ku-band applications is proposed. This two-stage amplifier with chip size of 8.554mm2 (3.64mmtimes2.35mm) is designed to fully match 50-Omega input and output impedance. Under 8V and 2000mA dc bias condition, the PA deliver 38.1dBm (6.5W) saturated output power, 10.5-dB small signal gain and peak power added efficiency of 24.6% from 13.6 to 14.2GHz. This MMIC also achieved the best power densities (760mW/mm2) at Ku band reported to date

A fully matched high linearity 2-W PHEMT MMIC power amplifier for 3.5 GHz applications

A 2-W monolithic microwave integrated circuit power amplifier, operating between 3.3 and 3.8GHz by implementing AlGaAs/InGaAs/GaAs pseudomorphic high electronic mobility transistor for the applications of wideband code division multiple access, wireless local loop, and multichannel multipoint distribution service, is demonstrated. This two-stage amplifier is designed to fully match 50/spl Omega/ input and output impedances. With a dual-bias configuration, the amplifier possesses the characteristics of 30.4dB small-signal gain and 34dBm 1-dB gain compression power with 37.1% power added efficiency. Moreover, with a single carrier output power level of 24dBm, high linearity with a 43.5-dBm third-order intercept point operating at 3.5GHz is also achieved.

A 26–38 GHz Monolithic Doubly Balanced Mixer

A novel configuration of doubly balanced mixer is presented for operating over the 26-38 GHz band. The monolithic microwave integrated circuit (MMIC) was implemented by GaAs 0.15 mum pHEMT technology with the compact size of 1times2.5 mm2. A 180deg hybrid circuit and two identical Marchand baluns were employed to achieve good port-to-port isolation. They also have wide band performance, make the mixer more compact, and simplify IF extraction. This mixer has a conversion loss of better than 6 dB, a dc-10 GHz IF bandwidth, and the LO-to-RF and LO-to-IF isolations are better than 20 dB and 29 dB, respectively.

A 16–44 GHz Compact Doubly Balanced Monolithic Ring Mixer

A novel and compact 16-44 GHz ultra-broadband doubly balanced monolithic ring mixer for Ku- to Ka-band applications implemented with a 0.15-mum pHEMT process is presented. The proposed mixer is composed of a C-band miniature spiral balun and a 180deg hybrid formed with an interdigital coupler, a low-pass pi-network, and a high-pass T-network. The 180deg hybrid eliminates the use of a cross-over structure for application in the balanced mixer, as well as provides an output port for the RF extraction of up-converter application. This proposed configuration leads to a die size of less than 0.8times0.8 mm2 . From the measured results, the mixer exhibits an 11-14 dB conversion loss, a 27-50 dB high LO-to-IF isolation over 16-44 GHz RF/LO bandwidth, and a 1-dB compression power of 14 dBm for both down- and up-converter applications.

A New Ka-Band Doubly BalancedMixer Based on Lange Couplers

A compact Ka-band doubly balanced diode mixer with new phase relationships is demonstrated. In this design, a novel configuration was employed to have good performance while keeping compact size and simple intermediate frequency (IF) extraction. It is flexible not only in layout design, but also in the reduction of IF inductance. The chip dimension is as small as 0.851.35 mm, implemented by using a 0.15 m PHEMT technology. This mixer has a conversion loss between 9 to 12 dB, a dc-3.5 GHz IF bandwidth, and a good port-to-port isolation in Ka band.