R. Yu

Active and nonlinear wave propagation devices in ultrafast electronics and optoelectronics

We describe active and nonlinear wave propagation devices for generation and detection of (sub)millimeter wave and (sub)picosecond signals. Shock-wave nonlinear transmission lines (NLTLs) generate /spl sim/4-V step functions with less than 0.7-ps fall times. NLTL-gated sampling circuits for signal measurement have attained over 700-GHz bandwidth. Soliton propagation on NLTLs is used for picosecond impulse generation and broadband millimeter-wave frequency multiplication. Picosecond pulses can also be generated on traveling-wave structures loaded by resonant tunneling diodes. Applications include integration of photodetectors with sampling circuits for picosecond optical waveform measurements and instrumentation for millimeter-wave waveform and network (circuit) measurements both on-wafer and in free space. General properties of linear and nonlinear distributed devices and circuits are reviewed, including gain-bandwidth limits, dispersive and nondispersive propagation, shock-wave formation, and soliton propagation. >

GaAs nonlinear transmission lines for picosecond pulse generation and millimeter-wave sampling

The GaAs nonlinear transmission line (NLTL) is a monolithic millimeter-wave integrated circuit consisting of a high-impedance transmission line loaded by reverse-biased Schottky contacts. The engineering of functional monolithic NLTLs is considered. Through generation of shock waves on the NLTL, the authors have generated electrical step functions with approximately 5 V magnitude and less than 1.4 ps fall time. Diode sampling bridges strobed by NLTL shock-wave generators have attained bandwidths approaching 300 GHz and have applications in instruments for millimeter-wave waveform and network measurements. The authors discuss the circuit design and diode design requirements for picosecond NLTL shock-wave generators and NLTL-driven sampling circuits. >

28-39 GHz distributed harmonic generation on a soliton nonlinear transmission line

A second-harmonic generation is reported in the 26-40-GHz band through soliton propagation on a GaAs monolithic nonlinear transmission line. At 20-dBm input power, a 20-diode structure attained <12-dB conversion loss for input frequencies from 13.5-18 GHz, with 9.3-dB minimum conversion loss, while a 10-diode structure attained <12-dB loss, 14-19.5 GHz (7.3-dB minimum). With reduction of conductor skin losses, broadband operation and peak conversion efficiencies approaching -3 dB are attainable.<<ETX>>

V-band and W-band broad-band, monolithic distributed frequency multipliers

Broadband V-band and W-band frequency multiplication is reported using soliton propagation on a GaAs monolithic device. With 24-dBm input, a doubler attained 17.4-dBm peak output power with at least a 52-63.1-GHz, 3-dB bandwidth, and a tripler attained 12.8-dBm peak output power with at least a 81-108.8-GHz, 3-dB bandwidth. These multipliers, fabricated with 3- mu m design rules on GaAs and driven by lower-frequency amplifiers. have applications as cost-effective sources in millimeter-wave systems. >

Bias stabilization for resonant tunnel diode oscillators

While resonant tunnel diodes (RTDs) are useful as submillimeter-wave oscillators, circuit design constraints imposed to suppress parasitic bias circuit oscillations have limited output powers to well below 1 mW. We report a 7-GHz RTD oscillator with a shunt regulator for bias circuit stabilization. With regulation, oscillator power is not limited by stability constraints. Regulation elements are readily integrated with RTDs to construct monolithic RTD oscillator arrays. >

Impulse compression using soliton effects in a monolithic GaAs circuit

A monolithic GaAs impulse compressor circuit which utilizes soliton wave propagation effects in nonlinear transmission lines has been fabricated. The circuits compress a 20 dBm, 8 GHz sinusoid to a train of 3.9 V peak to peak, 5.5 ps full width at half maximum impulses.

A broadband free-space millimeter-wave vector transmission measurement system

We report both broadband monolithic transmitter and receiver ICs for MM-wave electromagnetic measurements. The ICs use a nonlinear transmission line (NLTL) and a sampling circuit as a picosecond pulse generator and detector. The pulses are radiated and received by planar monolithic bow-tie antennas, collimated with silicon substrate lenses and off-axis parabolic reflectors. Through Fourier transformation of the received pulse, accurate 30-250 GHz free space gain-frequency and phase-frequency measurements are demonstrated. Systems design considerations are discussed, and a variety of MM-wave broadband transmission measurements are demonstrated. >

Capacitive-division traveling-wave amplifier with 340 GHz gain-bandwidth product

We report capacitive-division traveling-wave amplifiers having measured midband gains of 8 dB with a 1-98 GHz 3-dB-bandwidth, and 11 dB gain with a 1-96 GHz bandwidth. The capacitive-division topology raises the input Q of each cell, giving the amplifier increased bandwidth over conventional designs with the same active device technology; using 0.15-/spl mu/m gate length InGaAs/InAlAs HEMTs, bandwidths exceeding 150 GHz are feasible.<<ETX>>We report capacitive-division traveling-wave amplifiers having measured midband gains of 8 dB with a 1-98 GHz 3-dB-bandwidth, and 11 dB gain with a 1-96 GHz bandwidth. The capacitive-division topology raises the input Q of each cell, giving the amplifier increased bandwidth over conventional designs with the same active device technology; using 0.15-/spl mu/m gate length InGaAs-InAlAs HEMTs, bandwidths exceeding 150 GHz are feasible.<<ETX>>

Picosecond duration, large amplitude impulse generation using electrical soliton effects

We report two devices which generate picosecond duration electrical impulses using soliton propagation effects. A high repetition‐rate device has generated an 8.1 Vp‐p (87 mAp‐p), 4.5 ps full width at half‐maximum (FWHM) impulse train at a 31.5 GHz rate. A high compression ratio device has generated an 11.4 Vp‐p (122 mAp‐p), 5.1 ps FWHM impulse train at a 9 GHz rate (sinusoidal input), and a 12.1 Vp‐p (130 mAp‐p), 4.9 ps FWHM impulse train at a 3.22 GHz repetition rate (28 ps FWHM impulse‐train input).

Picosecond electrical spectroscopy using monolithic GaAs circuits

This article describes an experimental apparatus for free-space mm-wave transmission measurements (spectroscopy). GaAs nonlinear transmission lines and sampling circuits are used as picosecond pulse generators and detectors, with planar monolithic bowtie antennas with associated substrate lenses used as the radiating and receiving elements. The received pulse is 270 mV amplitude and 2.4 ps rise time. Through Fourier transformation of the received pulse, 30–250 GHz measurements are demonstrated with <=0.3 dB (rms) accuracy.