Robert E. Leoni

K-band receiver front-ends in a GaAs metamorphic HEMT process

In this paper, we present K-band receiver blocks fabricated in a state-of-the-art 0.18-/spl mu/m GaAs metamorphic high electron-mobility transistor (MHEMT) process using a 60% indium-content InGaAs channel. Several circuits are developed to demonstrate the superior noise performance and successful integration of K-band receiver components in such a process. We show a low-power three-stage low-noise amplifier (LNA) with a gain of 23 dB and a noise figure (NF) of less than 1.6 dB at 30 GHz. This LNA shows InP-like performance on a GaAs substrate with a high RF yield of 84%. This is the first report of a statistical yield analysis of an MHEMT integrated circuit. We also demonstrate on-chip integration of a single-stage amplifier with a diode subharmonic mixer for low-power and broad-band receiver performance. This down-converter exhibits a conversion loss of 3 dB, overall NF of 5 dB, and third-order input intercept point of -5 dBm from 26 to 30 GHz.

40-Gbit/s OEIC on GaAs substrate through metamorphic buffer technology

An optoelectronic integrated circuit operating in the 1.55-/spl mu/m wavelength range was realized on GaAs substrate through metamorphic technology. High indium content layers, metamorphically grown on a GaAs substrate, were used to fabricate the optoelectronic integrated circuits (OEICs) with -3 dB bandwidth of 40 GHz and 210 V/W of calculated responsivity. The analog OEIC photoreceiver consists of a 12-/spl mu/m, top-illuminated p-i-n photodiode, and a traveling wave amplifier (TWA). This receiver shows 6 GHz wider bandwidth than a hybrid photoreceiver, which was built using comparable, but stand-alone metamorphic p-i-n diode and TWA. With the addition of a buffer amplifier, the OEIC shows 7 dB more gain than the hybrid counterpart. To our knowledge, this is the first 40 Gbit/s OEIC achieved on a GaAs substrate operating at 1.55 /spl mu/m.

A Novel Broadband Even-Mode Matching Network for Marchand Baluns

In this paper, we present the development of an even-mode matching network for a Marchand balun to achieve 50-¿ match and high isolation at the balanced ports. A very wide matching bandwidth can be accomplished with the novel addition of an open-circuit stub to the network. Experimental results demonstrate that the even-mode matched balun achieves return losses that are greater than 15 dB at the balanced ports from 6 to 17 GHz. The measured isolation between the balanced ports is greater than 15 dB from 4 to 19 GHz. For the unbalanced port, the return loss is greater than 15 dB from 4 to 19 GHz. The measured insertion loss is less than 1 dB, and amplitude and phase imbalances are ±0.5 dB and ±5° from 4 to 18 GHz, respectively.

Wide-Bandwidth Power-Combining and Inverse Class-F GaN Power Amplifier at X-Band

In this paper, we present a wide bandwidth power amplifier (PA) utilizing a Marchand balun to achieve power combining and inverse class-F (class-F-1) matching. We have used a 4-to-1 balun and its out-of-band characteristics to achieve matching at the second and third harmonic for differential class-F-1 operation. Thus, the balun simultaneously acts as a combiner and harmonic matching network. The experimental results demonstrate that the prototype PA achieves an output power of 41.5 dBm at the 1-dB compression point (P1 dB), power-added efficiency of 55%, and gain of 10 dB over a fractional bandwidth of 40% from 8 to 12 GHz. Due to the differential operation, the class-F-1 PA has also achieved a measured second harmonic distortion of -50 dBc.

High efficiency push-pull inverse class f power amplifier using a balun and harmonic trap waveform shaping network

We present the design and development of a push-pull inverse class F power amplifier in X band using a novel harmonic matching network. The harmonic matching network is realized by a simple, low-loss, Marchand balun and a harmonic trap circuit. This novel harmonic matching network not only provides 3-dB power combining, but also enables waveform shaping for enhanced efficiency. This 1-stage power amplifier using discrete GaAs pHEMTs achieves a measured saturated output power of 33 dBm with a power added efficiency of 63% and a gain of 10 dB. This amplifier operates at 10 GHz with a 6% fractional bandwidth.

Active simultaneous harmonic source and load pull assisted by local polyharmonic distortion models

The efficiency of a power amplifier is a strong function of the core transistor technology and the circuitry that is wrapped around it. There are many theoretical approaches to obtaining full DC-to-RF conversion from an ideal transistor, however real-world technologies do not perform equally well with each. The parasitic reactances and non-ideal DC characteristics of a transistor technology result in matching and bias requirements that can deviate significantly from those of ideal theory. In this paper we describe the use of an active simultaneous source and load pull system that quickly ascertains the conditions required to achieve a transistor technologys peak efficiency performance. The speed with which the system is able to achieve these results is facilitated by local polyharmonic distortion models that provide a quick and reliable method for finding the path of steepest ascent.

A 23:1 bandwidth ratio balun on multilayer organic substrate

We present the design and development of a novel, super wide bandwidth balun on a multilayer organic Liquid Crystal Polymer (LCP) substrate. The balun has a measured bandwidth ratio of 23:1, from 80 MHz to 1860 MHz. Within the operating bandwidth, the balun achieves an input return loss of better than 10 dB, an insertion loss of better than 1 dB, an amplitude imbalance of better than 0.4 dB and a phase imbalance of better than 10 degree. The size of the balun is 40.64 mm × 40.64 mm or 0.22 λg × 0.22 λg, where λg is guided-wavelength at the center frequency of 970 MHz. This balun achieves the largest bandwidth ratio reported to date on a multi-layered printed circuit board.

Development of a low-loss multilayered broadband balun using twin-thickness thin-film

We present the development of a multilayered Marchand balun that operates over a 4-20 GHz bandwidth. The balun achieves a measured insertion loss of less than 0.5 dB from 4 to 17 GHz, and less than 0.7 dB from 17 to 20 GHz. Measured amplitude and phase imbalances are less than 0.5 dB and 5°, respectively within 4-20 GHz. The balun design employs a novel twin dielectric thin-film thickness structure to achieve a low insertion loss and a wide bandwidth.

A 6-18 GHz Push-Pull Power Amplifier with Wideband Even-Order Distortion Cancellation in LCP Module

We present the development of a microwave push-pull power amplifier (PA) module that achieves both high output power and wide bandwidth 2nd-order harmonic cancellation from 6 GHz to 18 GHz. Measured PldB output power for the push-pull PA is 31 dBm, while its 2nd-order harmonic distortion is reduced by a minimum 20 dB throughout the 6-18 GHz passband compared to a single PA. The 2nd-harmonic output of the push-pull PA was also measured to be lower than -40 dBc all the way up to 36 GHz. The PA module was integrated into a liquid crystal polymer (LCP) substrate that enables the design of wide bandwidth baluns with less than 0.5 dB and 6deg amplitude and phase imbalances, respectively.

Metamorphic optoelectronic integrated circuits

As the required operational bandwidth of photoreceivers is increased, it becomes desirable to monolithically integrate photodiodes and transistors in order to optimize performance and enhance yield. In this paper we describe our demonstration of material and process capabilities which allow us to integrate high electron mobility transistors and 1.55 /spl mu/m PIN photodiodes on one substrate. The demonstration vehicles used for this are a DC-45 GHz traveling wave amplifier and a photodiode with 12 /spl mu/m optical windows. Measured results of three interconnection approaches (standard attenuator, optimized lossy match, buffer amplifier) are described.