Engineering topics

Rebeiz, Gabriel M.

Publications and source records attributed to Rebeiz, Gabriel M..

At least 19 records

NASA NTRS1997

W-Band On-Wafer Measurement of Uniplanar Slot-Type Antennas

Uniplanar slot-type antennas such as coplanar waveguide fed single- and dual-polarized slot-ring antennas and double folded-slot antennas are characterized using a millimeter-wave network analyzer and on-wafer measurement techniques. The antennas are designed to be mounted on a dielectric lens to minimize power loss into substrate modes and realize high-gain antenna patterns. On-wafer measurements are performed by placing the antenna wafer on a thick dielectric spacer of similar e(sub t) and eliminating the reflection from the probe station chuck with time-domain gating. The measured results agree well with method-of-moments simulations.

Raman, Sanjay↗

NASA NTRS1995

155- and 213-GHz AlInAs/GaInAs/InP HEMT MMIC oscillators

We report on the design and measurement of monolithic 155- and 213-GHz quasi-optical oscillators using AlInAs/GaInAs/InP HEMTs (high-electron mobility transistors). These results are believed to be the highest frequency three-terminal oscillators reported to date. The indium concentration in the channel was 80% for high sheet charge and mobility. The HEMT gates were fabricated with self-aligned sub-tenth-micrometer electron-beam techniques to achieve gate lengths on the order of 50 nm and drain-source spacing of 0.25 micron. Planar antennas were integrated into the fabrication process resulting in a compact and efficient quasi-optical Monolithic Millimeter-wave Integrated Circuit (MMIC) oscillator.

TRT-EXPERIMENTAL↗

NASA NTRS1995

Low-cost 20-22 GHz MIC active receiver/radiometer

A microwave integrated circuit active receiver is built and tested at 19-25 GHz. The receiver consists of a planar CPW-fed double folded-slot antenna coupled to a six-stage MESFET (metal semiconductor field effect transistors) amplifier and followed by a planar Schottky-diode detector. The folded-slot antenna on a GaAs half-space results in a wide frequency bandwidth suitable for MMIC amplifiers. The measured system performance show a video responsivity close to 1 GV/W at 20 GHz with a 3-dB bandwidth of 1500 MHz. A novel method which uses the planar video detector after the amplifier stages as an RF (radio frequency) mixer is used to measure the noise-figure of the direct detection radiometer. The system noise figure is 4.8 dB at 22 GHz. The radiometer sensitivity to a hot/cold load is 3.8 mu V/K. The measured antenna patterns show a 90% Gaussicity at 20-22 GHz. The active MIC receiver can be integrated monolithically for low-cost applications and is well suited for millimeter-wave linear imaging arrays.

PLANAR SCHOTTKY DIODE DETECTOR↗

NASA NTRS1993

A 26 to 220 GHz harmonic mixer-receiver

A wideband mm-wave harmonic mixer-receiver has been developed using a wideband integrated-circuit antenna, a back-to-back Schottky-barrier diode chip and microwave circuit design. The design is planar, simple to build and yields excellent performance from 26 to 180 GHz. Application areas include wideband early warning systems, wideband search and rescue systems and the extension of spectrum analyzer and power meter range to the mm-wave region.

Kormanyos, Brian K.↗

NASA NTRS1993

A wide-band 760-GHz planar integrated Schottky receiver

A wideband planar integrated heterodyne receiver has been developed for use at submillimeter-wave to FIR frequencies. The receiver consists of a log-periodic antenna integrated with a planar 0.8-micron GaAs Schottky diode. The monolithic receiver is placed on a silicon lens and has a measured room temperature double side-band conversion loss and noise temperature of 14.9 +/- 1.0 dB and 8900 +/- 500 K, respectively, at 761 GHz. These results represent the best performance to date for room temperature integrated receivers at this frequency.

Gearhart, Steven S.↗

NASA NTRS1993

A 250 GHz planar low noise Schottky receiver

A planar quasi-optical Schottky receiver based on the quasi-integrated horn antenna has been developed and tested over the 230-280 GHz bandwidth. The receiver consists of a planar GaAs Schottky diode placed at the feed of a dipole-probe suspended on a thin dielectric membrane in an etched-pyramidal horn cavity. The diode has a 1.21 micron anode diameter and a low parasitic capacitance due to the use of an etched surface channel. The antenna-mixer results in a measured DSB conversion loss and noise temperature at 258 GHz of 7.2 dB +/- 0.5 dB and 1310 K +/- 70 K, respectively, at room temperature. The design is compatible with SIS mixers, and the low cost of fabrication and simplicity makes it ideal for submillimeter-wave imaging arrays requiring a 10-20 percent bandwidth.

Ali-Ahmad, Walid Y.↗

NASA NTRS1993

An 86-106 GHz quasi-integrated low noise Schottky receiver

An integrated planar receiver was developed and tested over the 82-112 GHz bandwidth. The quasi-integrated antenna used in the receiver has a high gain, a high Gaussian coupling efficiency, and a wide bandwidth. The novel mixer design consists of a planar GaAs Schottky diode placed at the feed of a dipole-probe suspended inside an integrated horn antenna. The diode uses an etched surface channel and a planar air bridge for reduced parasitic capacitance. At 92 GHz, the room-temperature antenna-mixer exhibits a double sideband conversion loss and noise temperature of 5.5 +/- 0.5 dB and 770 K +/- 50 K, respectively. The measured DSB conversion loss and noise temperature over a 20 GHz bandwidth (86 GHz-106 GHz) remain less than 6.2 dB +/- 0.5 dB and 1000 K +/- 50 K, respectively. The low cost of fabrication and simplicity of the design makes it ideal for millimeter- and submillimeter-wave receivers.

Ali-Ahmad, Walid Y.↗

NASA NTRS1992

Millimeter-wave and terahertz integrated circuit antennas

This paper presents a comprehensive review of integrated circuit antennas suitable for millimeter and terahertz applications. A great deal of research was done on integrated circuit antennas in the last decade and many of the problems associated with electrically thick dielectric substrates, such as substrate modes and poor radiation patterns, have been understood and solved. Several new antennas, such as the integrated horn antenna, the dielectric-filled parabola, the Fresnel plate antenna, the dual-slot antenna, and the log-periodic and spiral antennas on extended hemispherical lenses, have resulted in excellent performance at millimeter-wave frequencies, and are covered in detail in this paper. Also, a review of the efficiency definitions used with planar antennas is given in detail in the appendix.

Rebeiz, Gabriel M.↗

NASA NTRS1992

94 GHz integrated horn monopulse antennas

A monolithic azimuthal monopulse antenna for 94 GHz applications has been developed. The structure consists of a single dipole suspended in one plane of an integrated horn cavity to obtain the sum pattern, and an antiparallel pair of dipoles suspended in a different plane of the same horn cavity to achieve the difference pattern. Pattern measurements of microwave models and on the millimeter-wave antennas show good agreement with theory and exhibit symmetry with a sharp -30 dB null at broadside for the difference antenna. Microwave model measurements show input impedances close to 50 Ohms, with greater than -25 dB isolation between sum and difference antennas across a 10 percent bandwidth.

Ling, Curtis C.↗

NASA NTRS1992

High-gain step-profiled integrated diagonal horn-antennas

A new step-profiled integrated-horn antenna is proposed. The antenna allows gains in the range of 17-20 dB to be achieved using standard (100) silicon wafers. The antenna is diagonally fed and exhibits very good circular symmetry within the 10-dB beamwidth. It has a fundamental Gaussian coupling efficiency of 83 percent. It is demonstrated that the profiled antenna has a radiation pattern similar to that of its smooth envelope horn, provided that the discontinuity between successive wafers does not exceed 0.15 lambda. The integrated stepped-profile horn performs much better than a corresponding smooth 70 deg flare-angle integrated horn of the same aperture size. The integrated step-profile horn is very well-suited for radio-astonomical and remote-sensing millimeter-wave imaging arrays requiring a large number of focal-plane elements.

Eleftheriades, George V.↗

NASA NTRS1992

Millimeter-wave double-dipole antennas for high-gain integrated reflector illumination

A double-dipole antenna backed by a ground plane has been fabricated for submillimeter wavelengths. The double-dipole antenna is integrated on a thin dielectric membrane with a planar detector at its center. Measured feed patterns at 246 GHz agree well with theory and demonstrate a rotationally symmetric pattern with high coupling efficiency to Gaussian beams. The input impedance is around 50 ohms, and will match well to a Schottky diode or SIS detector. The double-dipole antenna served as the feed for a small machined parabolic reflector. The integrated reflector had a measured gain of 37 dB at 119 microns. This makes the double-dipole antenna ideally suited as a feed for high resolution tracking or for long focal length Cassegrain antenna systems.

Filipovic, Daniel F.↗

NASA NTRS1992

A 20-dB quasi-integrated horn antenna

A multimode quasi-integrated dipole-fed horn antenna is presented with a performance comparable to that of waveguide-fed corrugated horn antennas. The antenna has been designed using fullwave analysis and has been fabricated and tested at 91 GHz. The horn has a gain of 20 dB with very symmetric patterns, a Gaussian coupling efficiency of 97 percent, and a cross-polarization level of -22.7 dB. The antenna provides a significant improvement in integrated antenna designs and is suitable for millimeter-wave communication and radar systems and as a Gaussian-beam launcher in quasi-optical receiver systems.

Eleftheriades, George V.↗

NASA NTRS1992

Integrated horn antennas for millimeter-wave applications

The development of integrated horn antennas since their introduction in 1987 is reviewed. The integrated horn is fabricated by suspending a dipole antenna, on a thin dielectric membrane, in a pyramidal cavity etched in silicon. Recent progress has resulted in optimized low- and high-gain designs, with single and double polarization for remote-sensing and communication applications. A full-wave analysis technique has resulted in an integrated antenna with performance comparable to that of waveguide-fed corrugated-horn antennas. The integrated horn design can be extended to large arrays, for imaging and phased-array applications, while leaving plenty of room for the RF and IF processing circuitry. Theoretical and experimental results at microwave frequencies and at 90 GHz, 240 GHz, and 802 GHz are presented.

Rebeiz, Gabriel M.↗

NASA NTRS1992

Active CPW-fed slot antennas for power combining applications

We have combined integrated circuit antenna technology with microwave oscillator design to build an active slot-oscillator. The design is planar, does not require via holes and is compatible with monolithic transistor technology. The CPW-fed antenna impedance is calculated using a full-wave analysis technique. Slot-oscillators were built at 7, 13, and 22 GHz, and the predicted oscillation frequencies agree well with experiments. The design is easily scaled to millimeter-wave frequencies and can be extended to power combining arrays.

Kormanyos, Brian K.↗

NASA NTRS1992

Progress in integrated-circuit horn antennas for receiver applications. Part 1: Antenna design

The purpose of this work is to present a systematic method for the design of multimode quasi-integrated horn antennas. The design methodology is based on the Gaussian beam approach and the structures are optimized for achieving maximum fundamental Gaussian coupling efficiency. For this purpose, a hybrid technique is employed in which the integrated part of the antennas is treated using full-wave analysis, whereas the machined part is treated using an approximate method. This results in a simple and efficient design process. The developed design procedure has been applied for the design of a 20, a 23, and a 25 dB quasi-integrated horn antennas, all with a Gaussian coupling efficiency exceeding 97 percent. The designed antennas have been tested and characterized using both full-wave analysis and 90 GHz/370 GHz measurements.

Eleftheriades, George V.↗

NASA NTRS1992

Progress in integrated-circuit horn antennas for receiver applications. Part 2: A 90 GHz quasi-integrated horn antenna receiver

A receiver belonging to the family of integrated planar receivers has been developed at 90 GHz. It consists of a planar Schottky-diode placed at the feed of a dipole-probe suspended inside an integrated horn antenna. The measured planar mixer single-sideband conversion loss at 91.2 GHz (LO) with a 200 MHz IF frequency is 8.3dB plus or minus 0.3dB. The low cost of fabrication and simplicity of this design makes it ideal for millimeter and submillimeter-wave receivers.

Ali-Ahmad, Walid Y.↗

NASA NTRS1992

Double-slot antennas on extended hemispherical dielectric lenses

An investigation of the coupling efficiencies to a gaussian-beam of a double-slot antenna on a hyperhemispherical lens is presented. It is shown that both lenses couple equally well to an appropriate gaussian beam (about 80 percent). The radiation patterns of both lenses with a double-slot antenna are computed using the ray-tracing method. The experimental radiation patterns are presented and show close agreement to the theoretically computed patterns.

Filipovic, Daniel F.↗

NASA NTRS1991

Millimeter-wave integrated-horn antennas. I - Theory. II - Experiment

Full-wave analysis is employed to determine the far-field pattern and input impedance of a dipole-fed horn antenna in a ground plane, and the theoretical results are compared with mm-wave and microwave data. The theoretical work exploits the Green's function corresponding to the horn structure and the method of moments. It is determined that the horn should have 70 sections/wavelength and 50 secondary modes for optimized accuracy, and certain dipole positions can reduce the resonance to zero. The experimentally derived impedance and radiation patterns agree with the constraints developed theoretically. The 70-degree flare-angle horn with selected dipole positions and horn apertures yields good radiation patterns, cross-polarization levels, and resonant dipole impedances. The conclusions are of interest to the development of the horn antennas etched in Si/GaAs for applications to zero-visibility tracking, radio astronomy, plasma diagnostics, and remote sensing.

Eleftheriades, George V.↗