Determining Two-Port S-Parameters from a One-Port Measurement Using a Novel Impedance-State Test Chip

A novel custom high-speed test chip and data reduction technique that allows for the accurate determination of the two-port S-parameters of a passive network from a set of one-port measurements is presented. A typical application for this technique is high-speed integrated circuit package characterization where one-port is of a microelectronic size scale and inside the package. The test chip is designed to operate up to 20 GHz

High Speed Traveling Wave Electrooptic Intensity Modulator with a Doped PIN Semiconductor Junction

A high-electrooptic-efficiency Mach-Zehnder intensity modulator is demonstrated with a bandwidth exceeding 40 GHZ. The 1 mm-long modulator has a switching voltage comparable to undoped semiconductor designs of much greater length

Dual SAW sensor technique for determining mass and modulus changes in thin silicate films during gas adsorption

Surface acoustic wave (SAW) sensors, which are sensitive to a variety of surface changes, have been widely used for chemical and physical sensing. The ability to control or compensate for the many surface forces has been instrumental in collecting valid data. In cases where it is not possible to neglect certain effects, such as frequency drift with temperature, methods such as the dual sensor technique have been utilized. This paper describes a novel use of a dual sensor technique, using two sensor materials, Quartz and GaAs, to separate out the contributions of mass and modulus of the frequency change during gas adsorption experiments. The large modulus change in the film calculated using this technique, and predicted by the Gassmann equation, provide a greater understanding of the challenges of SAW sensing

Superconducting active impedance converter

This invention is comprised of a transimpedance amplifier for use with high temperature superconducting, other superconducting, and conventional semiconductor allows for appropriate signal amplification and impedance matching to processing electronics. The amplifier incorporates the superconducting flux flow transistor into a differential amplifier configuration which allows for operation over a wide temperature range, and is characterized by high gain, relatively low noise, and response times less than 200 picoseconds over at least a 10--80 K temperature range. The invention is particularly useful when a signal derived from either far-IR focal plane detectors or from Josephson junctions is to be processed by higher signal/higher impedance electronics, such as conventional semiconductor technology

High-speed vertical cavity surface emitting lasers

High speed modulation and pulsing are reported for oxide-confined vertical cavity surface emitting laser diodes (VCSELs) with inverted doping and proton implantation to reduce the extrinsic limitations

High-Efficiency, Low-Voltage, Compound Semiconductor Devices for Microwave and MM-Wave Power Amplifiers

Improvements in the last decade in InP materials growth, device processing techniques, characterization, and circuit design have enabled solid-state power performance through 122 GHz. Although originally targeted for low-noise and power performance at mm-wave frequencies (>30 GHz), InP HEMTs could become the preferred device for frequencies as low as 800 MHz. This investment has benefited the microwave frequency regime with higher efficiency and power densities at lower operating voltages. State-of-the-art microwave performance at lower operating voltage provides a path to smaller, lighter-weight systems in the battery operated arena of commercial and defense electronics. This paper describes an InP HEMT technology being investigated for many power and low-noise amplifier applications from UHF to W-band frequencies. Specifically the technology demonstrated 640mW/mm power density, 27 dB gain, and 84% power-added efficiency at L-band with a bias of 3.0 volts. Based on the author's literature search, this is a record efficiency at L-band with an operating voltage of less than 5 volts

Phased-array antenna control by a monolithic photonic integrated circuit, COMPASS

Phased-array antenna systems are well known for rapid beam steering and their ability to bring high power to the target. Such systems are also quite complex and heavy, which have limited their usefulness. The issues of weight, size, power use, and complexity have been addressed through a system named COMPASS (Coherent Optical Monolithic Phased Array Steering System). All phased-array antenna systems need: (1) small size; (2) low power use; (3) high-speed beam steering; and (4) digitally-controlled phase shifting. COMPASS meets these basic requirements, and provides some very desirable additional features. These are: (1) phase control separate from the transmit/receive module; (2) simple expansion to large arrays; (3) fiber optic interconnect for reduced sensitivity to EMI; (4) an intrinsically radiation-hard GaAs chip; and (5) optical power provided by a commercially available continuous wave (CW) laser. 4 refs., 8 figs

High-Q photonic bandgap resonant cavities: From mm-wave to optical regime

The authors have realized a new class of high-Q resonant cavity using two-dimensional photonic bandgap (PBG) structures and showed that its Q-value can be as high as {approximately}23,000 in the mm-wave regime. They further show that its modal properties, such as the resonant frequency, modal linewidth and number of modes, can be tuned by varying the cavity size. In addition, they present a new nano-fabrication technique for constructing PBG resonant cavities in the near infrared and visible spectral regime