Showing papers on "Return loss published in 1993"
14 Jun 1993
TL;DR: In this article, a W-band probe based on a coaxial line design has been developed, with built-in bias tee, 2-dB insertion loss and better than 12-dB return loss from 75 GHz to 110 GHz.
Abstract: A W-band wafer probe based on a coaxial line design has been developed. With built-in bias tee, 2-dB insertion loss and better than 12-dB return loss from 75 GHz to 110 GHz are achieved. A probe without bias tee has 1.3-dB loss and 1.5-dB return loss at 94 GHz when optimized for narrowband application. S-parameters of discrete transistors and circuits have been accurately measured from 75 GHz to 110 GHz. The noise figure of active circuits has also been measured at W-band with these probes. >
44 citations
Patent•
14 Jun 1993TL;DR: In this article, a return loss meter (100) for base stations comprises a first transceiver (10), having a first transmitter (12), a first receiver (22 and 30), and a first antenna (20), a second transceiver(50) having a second transmitter (52, a second receiver (62 and 70) and a second antenna (60), where the first transceivers and the second transcevers are cross-coupled using at least one directional coupler (16) capable of being switched.
Abstract: A return loss meter (100) for base stations comprises a first transceiver (10) having a first transmitter (12), a first receiver (22 and 30), and a first antenna (20), a second transceiver (50) having a second transmitter (52), a second receiver (62 and 70), and a second antenna (60), wherein the first transceiver and the second transceiver are cross-coupled using at least one directional coupler (16) capable of being switched. The return loss meter includes a device for measuring reflected and transmitted power of the first antenna via a first directional coupler (16) capable of being switched and via a device (74) capable of measuring received signal strength at the second receiver and a device for measuring reflected and transmitted power of the second antenna via a second directional coupler (56) capable of being switched and via a device (34) capable of measuring received signal strength at the first receiver.
33 citations
Patent•
20 May 1993
TL;DR: In this article, the offset of two common fiber axes is controlled to achieve a controlled transverse misalignment loss while the ends of the fibers are maintained in physical contact under a spring force of the connectors such that a high return loss is achieved.
Abstract: Light attenuation through a high return loss fixed attenuator is achieved by controlling the offset of two common fiber axes to achieve a controlled transverse misalignment loss while the ends of the fibers are maintained in physical contact under a spring force of the connectors such that a high return loss is achieved.
22 citations
28 Jun 1993
TL;DR: In this article, an experimental investigation of bandwidth enhancement of dielectric resonator antennas (DRAs) using parasitic elements is reported, and substantial bandwidth enhancement for the HE/sub 11/spl delta/δ-mode of the stacked geometry and for the H/sub 13/spl Δ-mode in the coplanar collinear geometry has been demonstrated.
Abstract: An experimental investigation of bandwidth enhancement of dielectric resonator antennas (DRAs) using parasitic elements is reported. Substantial bandwidth enhancement for the HE/sub 11/spl delta// mode of the stacked geometry and for the HE/sub 13/spl delta// mode of the coplanar collinear geometry has been demonstrated. Excellent radiation patterns for the HE/sub 11/spl delta// mode were also recorded. Because of excellent return loss and radiation characteristics, the DRA should be excited in HE/sub 11/ mode when used as radiating elements in an array. >
22 citations
TL;DR: In this article, the design and demonstration of an octave bandwidth impedance matching network for directly modulated diode lasers were considered, and the laser was matched to 50 Omega over the 2-4GHz band, achieving greater than 13dB return loss and a dramatic 10dB improvement in fiber link insertion loss and sensitivity.
Abstract: The design and demonstration of an octave bandwidth impedance matching network for directly modulated diode lasers are considered. Compact semilumped matching structures have been designed and fabricated at microwave frequencies with near theoretical performance. The laser was matched to 50 Omega over the 2-4-GHz band, achieving greater than 13-dB return loss and a dramatic 10-dB improvement in fiber link insertion loss and sensitivity. Excellent agreement was obtained between measured and simulated fiber link performance. >
21 citations
[...]
TL;DR: In this paper, a W-band probe using a ridge-trough waveguide as a transition from a rectangular waveguide input to the coplanar waveguide (CPW) used on the probe board output is presented.
Abstract: A W-band (75-110 GHz) wafer probe was successfully designed and built. The probe uses a ridge-trough waveguide as a transition from a rectangular waveguide input to the coplanar waveguide (CPW) used on the probe board output. Typical insertion loss and return loss figures were 3.5 dB and better than 13 dB, respectively. Losses were minimized in the CPW probe board by attention to conductor loss and taper design; in addition, the transition from rectangular waveguide to ridge-trough waveguide led to an insertion loss less than 1 dB. A crosstalk figure of better than -43 dB was achieved, which is important for accurate calibrations. These performance specifications allowed measured data to be corrected by a VNA for some W-band HEMT (high electron mobility transistor) devices. >
18 citations
TL;DR: In this article, an analysis method for the broadband rectangular microstrip antenna geometry using E-plane gap coupling is considered, and the return loss of the designed broadband antenna is computed theoretically and compared with experimental results for illustrating the usefulness of this method.
Abstract: An analysis method for the broadband rectangular microstrip antenna geometry using E-plane gap coupling is considered. The return loss of the designed broadband antenna is computed theoretically and compared with experimental results for illustrating the usefulness of this method.
11 citations
14 Jun 1993
TL;DR: In this article, the analysis and design of a circular ridged waveguide evanescent mode bandpass filter is described and two and three resonators filters are presented for the 30 GHz range.
Abstract: The analysis and design of a circular ridged waveguide evanescent mode bandpass filter are described. Two and three resonators filters are presented for the 30 GHz range. Insertion loss is typically below 1 dB and return loss is better than 20 dB, on the average. The full-wave FDTLM (frequency-domain transmission line matrix) method is used to compute the generalized S-parameters of the overall filter structures including the effect of finite metalization thickness and model interaction between filter discontinuities. A comparison to other filter structures in circular waveguides shows excellent agreement between measured and computed results. >
9 citations
TL;DR: In this paper, a planar antenna fed by electromagnetically coupled coplanar waveguide (CPW) has been fabricated on a single layer substrate with various thicknesses, and was studied experimentally.
Abstract: Planar antennas fed by electromagnetically coupled coplanar waveguide (CPW) have been fabricated on a single layer substrate with various thicknesses, and been studied experimentally. To suppress the spurious mode due to the parallel plate structure in the antenna system, short pins are inserted near the feeding point of the coplanar line. The measurement results of this antenna demonstrated high performance in both return loss and radiation pattern.
9 citations
TL;DR: In this article, a wideband and low-loss transition from conductor-backed coplanar waveguide to a modified, conductor-backward coplanara strip transmission line is presented.
Abstract: The Letter presents a wideband and low-loss transition from conductor-backed coplanar waveguide to a modified, conductor-backed coplanar strip transmission line. The measured insertion loss is less than 1 dB up to 4.8 GHz and the return loss is greater than 12 dB. To reduce undesired modes two dielectric layers are used between the circuit and the conductor backing.
9 citations
TL;DR: In this article, a pseudomorphic HEMT on an alumina substrate was used to integrate epitaxial lift-off devices and microstrip circuits, achieving a maximum gain of 6.8 dB and a return loss of -14 dB at 10.4 GHz.
Abstract: A process to integrate epitaxial lift-off devices and microstrip circuits has been demonstrated using a pseudomorphic HEMT on an alumina substrate. The circuit was a 10-GHz amplifier with the interconnection between the device and the microstrip circuit being made with photolithographically patterned metal. The measured and modeled response correlated extremely well with a maximum gain of 6.8 dB and a return loss of -14 dB at 10.4 GHz. >
01 Sep 1993
TL;DR: In this article, a single stage four section 1-55 GHz GaAs monolithic distributed amplifier in coplanar technology has been developed and achieved gain of more than 5 dB, the noise figure between 10 - 40 GHz less than 5.5 dB and the return loss is better than 10 dB.
Abstract: A single stage four section 1-55 GHz GaAs monolithic distributed amplifier in coplanar technology has been developed. The achieved gain is more than 5 dB, the noise figure between 10 - 40 GHz less than 5.5 dB and the return loss is better than 10 dB. The active devices for the amplifier are 0.2 ?m recessed gate AlGaAs HEMTs. The chip dimensions are 1.5 mm × 1.5 mm including bias networks.
28 Jun 1993
TL;DR: In this paper, the application of the transmission line matrix (TLM) method to analyzing flared notch elements in an infinite array environment is presented and the correlation between measured and computed return loss data is examined and shown to be excellent.
Abstract: The application of the transmission line matrix (TLM) method to analyzing flared notch elements in an infinite array environment is presented. The correlation between measured and computed return loss data is examined and shown to be excellent. It is concluded that generalized electromagnetic simulation tools such as TLM are allowing analysis of complex antenna element types such as printed circuit flared notch elements. By imposing appropriate periodic boundary conditions, phased array environments can be simulated. Since the analysis is performed in the time domain, broadband frequency response is obtained in one computer run. The code also allows improved understanding of the complex behavior of radiating elements in an array environment. >
TL;DR: In this article, a wavelength-tunable source and a wavemeter are used to measure chromatic dispersion and modal interference levels in addition to transmission attenuation, return loss, and fiber length.
Abstract: Introducing a wavelength-tunable source and a wavemeter, make it possible to modify a conventional optical time-domain reflectometer (OTDR) to measure chromatic dispersion and modal interference levels in addition to transmission attenuation, return loss, and fiber length.
14 Jun 1993
TL;DR: In this article, an optimization process is used to find the T-junction and step dimensions that yield a low reflection coefficient in one of the Tjunction arms over a wide frequency band.
Abstract: Scattering parameters of waveguide and ridge waveguide stepped T-junctions are obtained using an extension of the three plane mode matching method. An optimization process is used to find the T-junction and step dimensions that yield a low reflection coefficient in one of the T-junction arms over a wide frequency band. The optimized wideband T-junctions are useful in the design of wideband high power dividers, diplexers and multiplexers. A wideband 3-dB T-junction was optimized and verified by measurement. The optimization model for the wideband diplexer was implemented. Using this model, a C-band T-junction waveguide diplexer with total 31% bandwidth and return loss better than 22 dB in pass bands was designed. >
TL;DR: An arrayed hybrid filter/coupler consisting of four waveguide-type wavelength-insensitive couplers and a thin dielectric filter has been developed for application to an in-service optical fiber testing system as discussed by the authors.
Abstract: An arrayed hybrid filter/coupler consisting of four waveguide-type wavelength-insensitive couplers and a thin dielectric filter has been developed for application to an in-service optical fibre testing system. The device was designed to combine a 1.31 μm communication light and a 1.55 μm test light with a ratio of 80:20%. The measured performance of a prototype device exhibited an excess loss of 0.6 dB, a return loss attenuation of >45dB and a crosstalk attenuation for the test light of >60dB.
TL;DR: In this article, a coplanar waveguide antenna (CWA) was proposed and investigated experimentally and the measured return loss showed that the radiation mainly comes from the slot surrounding the open coplanaran waveguide circuit.
Abstract: A coplanar waveguide antenna (CWA) is proposed and investigated experimentally. The CWA consists of an open coplanar waveguide circuit and is fed by a coplanar waveguide with a characteristic impedance of 50 Ω. The measured return loss shows that the radiation mainly comes from the slot surrounding the open coplanar waveguide circuit. The area of the CWA is about 1/8 that of the corresponding microstrip antenna. © 1993 John Wiley & sons, Inc.
10 Oct 1993
TL;DR: In this paper, the MILSTAR EHF phased array communication antennas have been developed that could improve the manufacturability and cost of the EHF communication antennas by using MMIC amplifiers.
Abstract: 20 GHz low-noise and 44 GHz power MMIC amplifiers have been developed that could improve the manufacturability and cost of MILSTAR EHF phased array communication antennas. The six-stage power amplifier has 32.7 dB gain with 16.7 dBm output power and 17% power added efficiency. The chip measures 1.79 mm/sup 2/ and operates off two supplies. The four-stage LNA demonstrates 26 dB gain with 2.2 dB noise figure and 15 dB return loss. The LNA chip measures 1.18 mm/sup 2/ and operates off a single supply. >
TL;DR: In this article, a fully planar transition between two microstrip lines with side changed metallisation patterns is presented, suited to connecting a planar antenna to hermetically sealed integrated circuits.
Abstract: A novel fully planar transition between two microstrip lines with side changed metallisation patterns is presented. This transition is suited to connecting a planar antenna to hermetically sealed integrated circuits. The measured return loss between 36 and 40 GHz was 20 dB. A broader operating bandwidth can be expected
Patent•
23 Mar 1993
TL;DR: A modified branch line coupler amplitude equalizer circuit employing cross arms and branch lines of varying lengths and impedances to minimize the return loss of the circuit was proposed in this article, where the cross arms were replaced by branch lines.
Abstract: A modified branch line coupler amplitude equalizer circuit employing cross arms and branch lines of varying lengths and impedances to minimize the return loss of the circuit.
Patent•
13 Aug 1993
TL;DR: In this paper, a non-linear processor to be used as a signal limiter or a predistortion equalizer has four ports and a 3dB directional coupler 14, where a signal to be distorted is supplied to a 1st port 12 of the coupler and supplied through 2nd and 3rd ports 16 and 28 to a pair of nonlinear circuits 399 and 699.
Abstract: PURPOSE: To provide a non-linear signal transforming device matching the power levels over a wide range. CONSTITUTION: A non-linear processor to be used as a signal limiter or a predistortion equalizer has four ports and a 3dB directional coupler 14. A signal to be distorted is supplied to a 1st port 12 of the coupler and supplied through 2nd and 3rd ports 16 and 28 to a pair of non-linear circuits 399 and 699. The respective non-linear circuits have the source/drain trnasmission line of the FET. The respective non-linear circuits form a non-linear reflection circuit for reflecting energy back to the related port of the coupler while being grounded, namely, short-circuited. The non-linear reflected energy is received by two ports 16 and 28 of the coupler, coupled and appears at a 4th port 12 of the coupler. The input return loss of the processor is improved by mutually matching the non-linear circuits.
TL;DR: In this article, an end-fire TE/sub 221/mode of a hemispherical dielectric resonator (DR) antenna fed by a microstripline through an aperture on the ground plane is investigated both theoretically and experimentally.
Abstract: The end-fire TE/sub 221/ mode of a hemispherical dielectric resonator (DR) antenna fed by a microstripline through an aperture on the ground plane is investigated both theoretically and experimentally. The magnetic field Green function is presented for the evaluation of the return loss. The effects of slot position, slot length and slot width on the return loss are studied and discussed. >
28 Jun 1993
TL;DR: In this paper, a full-wave combined modal expansion and aperture field integration method is applied for the efficient design of profiled corrugated horns with circular, rectangular or combined cross-section.
Abstract: A full-wave combined modal expansion and aperture field integration method is applied for the efficient design of profiled corrugated horns with circular, rectangular or combined cross-section The generalized modal S-matrix combination of adequate key building blocks, ie, the circular, rectangular, or rectangular-to-circular waveguide step discontinuity, takes the influence of the higher-order modes and the aperture effect rigorously into account An optimized broadband profiled corrugated circular horn design example utilizing 40 varying slot elements with a rectangular waveguide input section demonstrates the usefulness of the method by achieving more than 26dB return loss, about 20 dB gain, and less than -30dB cross-polarization for a bandwidth of about 17:1 The theory is verified by comparison with available measurements >
28 Jun 1993
TL;DR: In this article, the authors proposed wide-angle conical monopoles as an alternative to whip-type antennas when adequate mounting surface is available, and the size can be adjusted to fit the available space with reduced efficiency resulting for smaller size.
Abstract: The authors propose wide-angle conical monopoles as an alternative to whip-type antennas when adequate mounting surface is available. The reduced height of wide-angle conical monopole systems makes possible: the use of edge loading for design versatility, nesting of multiple units for increasing bandwidth, and the incorporation of the antenna into the structure of a host vehicle so that no protrusion and a minimum of intrusion are required. A system of nested, wide-angle, conical monopoles can be made to cover a wide frequency band with near constant return loss. The size can be adjusted to fit the available space with reduced efficiency resulting for smaller size. A system within a hemisphere of radius /spl lambda//8 at the lowest resonance with return loss of 5 dB will have an efficiency of about 50% at the low end of the band. If the radius can be near /spl lambda//4 at the lowest frequency, the return loss will increase to about 10 dB and the efficiency will be near unity. >
01 Jan 1993
TL;DR: In this article, a digital 128*128 GaAs crossbar switch in high density interconnect (HDI) is considered, with particular emphasis on the implementation of devices in the HDI process, and results of measurements on a 3.6 cm-long by 243 mu m-wide microstrip transmission line demonstrate that -1.3dB insertion and -30-dB return loss can be achieved for frequencies up to 18 GHz with HDI technology.
Abstract: Multichip modules are considered, with particular emphasis on the implementation of devices in the high density interconnect (HDI) process. A digital 128*128 GaAs crossbar switch in HDI that operates at 400 MHz is considered. Results of measurements on a 3.6-cm-long by 243- mu m-wide microstrip transmission line demonstrate that -1.3-dB insertion and -30-dB return loss can be achieved for frequencies up to 18 GHz with HDI technology. Also considered is a C-band 6-GHz transmit/receive (T/R) HDI module that uses impedance-matched interconnects, exhibits no out-of-band oscillations, and results in a 40% size reduction compared to a conventional chip-and-wire counter-part using the same monolithic microwave integrated circuits. In addition, HDI's unique features allowed the construction of an 82-component voice processor/modem. It is pointed out that preliminary work shows the feasibility of a 10-A 50-W point-of-load 50-V-to-5-V DC-to-DC power supply for distributed applications. >
01 Mar 1993
TL;DR: A linearly tapered slot antenna (LTSA) has been fabricated on a high-resistivity silicon substrate and tested at C-band frequencies as discussed by the authors, where the LTSA is electromagnetically coupled to a coplanar waveguide (CPW) feed.
Abstract: A linearly tapered slot antenna (LTSA) has been fabricated on a high-resistivity silicon substrate and tested at C-band frequencies. The LTSA is electromagnetically coupled to a coplanar waveguide (CPW) feed. The measured radiation patterns, gain, and return loss are presented and discussed. The LTSA exhibits good impedance match and radiation patterns. >
28 Jun 1993
TL;DR: In this article, a planar circularly polarized microstrip patch array composed of 4/spl times/4 patches for space applications at S-band was designed and the measured results showed that the use of hybrid power splitters improved the return loss and the peak axial ratio but drastically reduced the antenna efficiency.
Abstract: The authors present the design technique and the measured results of a planar circularly polarized microstrip patch array composed of 4/spl times/4 patches for space applications at S-band. A comparison of the two array configurations shows that the use of hybrid power splitters improves the return loss and the peak axial ratio but drastically reduces the antenna efficiency. The improved array configuration keeps high efficiency over a wide frequency band. >
Patent•
13 Aug 1993
TL;DR: In this paper, at least one of the ridges of a square dielectric board 10 opposite to each other is cut off to vary the longitudinal and lateral size to attain the reception of a circularly polarized wave through degeneration separation.
Abstract: PURPOSE:To use the microstrip antenna for a linearly polarized wave for the antenna for a circularly polarized wave. CONSTITUTION:At least one of ridges of a square dielectric board 10 opposite to each other is cut off to vary the longitudinal and lateral size to attain the reception of a circularly polarized wave through degeneration separation. Without cutting off the entire two ridges opposite to each other, part of them or one side of them or the like is cut off and the return loss characteristic is varied by the fringing effect.
24 May 1993
TL;DR: The Wavetek 8003 Precision Scalar Analyzer and Hewlett-Packard 83623A Synthesized Sweeper used in the TWT Automated Test Station (TATS) at the Electronic Warfare Directorate of Warner Robins Air Logistics Center (WR-ALC/LN) provide CW power, pulsed RF power, insertion loss, gain, and return loss measurements in fixed frequency and swept modes as mentioned in this paper.
Abstract: Microwave measurement technology advances promote improved broadband testing. Typical microwave measurement techniques require: a scalar analyzer for insertion loss, gain, and return loss measurements; a power meter for accurate CW power measurements; and a peak power meter for pulsed RF measurements. Older scalar analyzers are not very useful in testing pulsed modes. The Wavetek 8003 Precision Scalar Analyzer and Hewlett-Packard 83623A Synthesized Sweeper used in the TWT Automated Test Station (TATS) at the Electronic Warfare Directorate of Warner Robins Air Logistics Center (WR-ALC/LN) provide CW power, pulsed RF power, insertion loss, gain, and return loss measurements in fixed frequency and swept modes. An absolute power mode provides accurate power measurements at the sensor input. A measurement minus pathcal mode (used for insertion loss and gain) returns relative power based on a stored path calibration reference. These new capabilities can be further improved by extending typical scalar analyzer calibration concepts. The precision scalar analysis topics and examples based on TATS development are discussed. Other techniques discussed include gain variation versus frequency analysis and swept saturated power tests. >
01 Oct 1993
TL;DR: In this article, a sectorial waveguide is fed by five identical probes at the end of a star-shaped feed line with five arms, which is placed in a trace between the sectoral waveguides.
Abstract: A compact broadband TE01-mode generator is presented. It consists of five identical sectorial waveguides which are stepped into an ordinary circular waveguide. These sectorial waveguides are fed by five identical probes at the end of a star-shaped feed line with five arms. This feed line is placed in a trace between the sectorial waveguides. A consequence of the five-fold symmetry is that the lowest parasitic mode which can be generated and propagated has a cutoff far above the frequency range of operation (9.5–10.5 GHz). The measurements show that the return loss is less than −15dB in the frequency range of operation. The mode purity is better than 99.4%.