Showing papers on "Return loss published in 1995"
TL;DR: In this paper, an all-fiber Mach-Zehnder interferometer with photo-induced Bragg gratings was used to drop/insert a single wavelength channel from/into a multiple-wavelength transmission link with 100 GHz channel-spacing at 1550 nm.
Abstract: A wavelength multiplexing/demultiplexing device is fabricated and used to drop/insert a single wavelength channel from/into a multiple wavelength transmission link with 100 GHz channel-spacing at 1550 nm. The device consists of an all-fiber Mach-Zehnder interferometer with photoinduced Bragg gratings. The following performances were measured: extraction/coupling efficiency =99.4%, excess loss 20 dB, and return loss >23 dB. >
219 citations
TL;DR: In this article, a class of lumped-element filters that uses capacitively-loaded inductors to give frequency-dependent inductance values is reported. But, it is difficult to realize narrowband filters (e.g., < 0.1% fractional bandwidth) in reasonably sized microstrip form due to the very weak coupling values required.
Abstract: Coupling between microstrip resonators decreases very slowly as a function of the resonator separation. Therefore, it is difficult to realize narrowband filters (e.g., <0.1% fractional bandwidth) in reasonably sized microstrip form due to the very weak coupling values required. In this paper, we report a class of lumped-element filters that uses capacitively-loaded inductors to give frequency-dependent inductance values. A novel frequency transformation technique is used in the design process. Using this approach, filter bandwidth is determined by the inductance slope of frequency-dependent inductors, dL/d/spl omega/. Large coupling capacitance, thus small coupling element separations, can still be used in narrowband microstrip filters to keep the filter layout compact. We present a 5-pole, 0.27% bandwidth YBa/sub 2/Cu/sub 3/O/sub 7/ high-temperature superconducting thin film microstrip prototype filter at 900 MHz, which has 1.2 dB insertion loss and 20 dB return loss. It was designed with the coupling capacitors of a 1% bandwidth filter, and then transformed to a 0.27% fractional bandwidth using an appropriate inductance slope parameter, dL/d/spl omega/. Measurement showed good agreement with theory.
61 citations
TL;DR: In this paper, the authors report a narrowband microstrip filter with low insertion loss and high power-handling capabilities made from YBa/sub 2/Cu/sub 3/O/sub 7/(-x) high-temperature superconducting films.
Abstract: We report narrowband microstrip filters with low insertion loss and high power-handling capabilities made from YBa/sub 2/Cu/sub 3/O/sub 7/(-x) high-temperature superconducting films. One 5-pole filter on a LaAlO/sub 3/ substrate, consisting of backward-coupled and forward-coupled resonators, can handle over 27 W input power at 10 K. It has 1% fractional bandwidth and 10-/spl Omega/ internal impedance. The insertion loss increase in passband at 10 K, as the input power changed from a few mW to 27 W, is less than 0.25 dB. We also report a forward-coupled microstrip filter centered at 2 GHz, with a 1.2% fractional bandwidth, 10-/spl Omega/ internal impedance, and parallel-coupled feed lines. We applied over 10 /spl Omega/ to the filter at 45 K without noticeable degradation of the filter performance. The insertion loss at 45 K is less than 0.2 dB. The return loss is better than 12 dB. >
53 citations
TL;DR: In this article, a 19-pole bandpass filter designed for the 900-MHz cellular communication band with 25-MHz bandwidth is reported using a compact forward-coupled approach in microstrip configuration.
Abstract: A 19-pole bandpass filter designed for the 900-MHz cellular communication band with 25-MHz bandwidth is reported using a compact forward-coupled approach in microstrip configuration. The filter was fabricated using 75-mm-diameter, double-side-coated YBa/sub 2/Cu/sub 3/O/sub 7/ (YBCO) high-temperature superconducting (HTS) thin films grown by a single-source MOCVD technique on a LaAlO/sub 3/ substrate. Measurement of the filter at 77 K showed a dissipation loss of 0.5 dB, corresponding to an average unloaded Q-factor of 10000 in 75-mm-diameter microstrip resonators. A minimum return loss of 15 dB was obtained from measurements at 77 K. >
52 citations
16 May 1995
TL;DR: In this paper, experimental and theoretical results are presented for membrane supported W-band bandpass filters which utilize silicon micromachining technology to create self-packaged, shielded circuits, and the measured filter performance shows very sharp cutoff with out of band attenuation better than 25 dB and input return loss better than 8 dB.
Abstract: Experimental and theoretical results are presented for membrane supported W-band bandpass filters which utilize silicon micromachining technology to create self-packaged, shielded circuits. A coupled line shielded microstrip implementation of a 5-element 0.5 dB equal ripple Chebyshev filter achieves a minimum insertion loss of 3.4 dB with a 6.1% bandwidth centered at 94.7 GHz. The measured filter performance shows very sharp cutoff with out of band attenuation better than 25 dB and input return loss better than 8 dB. Results are also presented for a 5-element filter that achieves a minimum insertion loss of 2.2 dB with an 11.3% bandwidth centered at 94.7 GHz, and a 3-element filter with 1.3 dB insertion loss and 16.4% bandwidth at 94.9 GHz. Efforts to model filter performance using commercially available software and FDTD techniques are discussed. >
49 citations
TL;DR: In this paper, a coplanar stripline to microstrip line transition is experimentally demonstrated and modelled using the finite difference time domain technique, and the measured insertion loss and return loss for two back-to-back transitions with a short length of micro-strip line in between are better than 2.4 and 10 dB, respectively, over the frequency range of 5.1 -6.1 GHz.
Abstract: A new coplanar stripline to microstrip line transition is experimentally demonstrated and modelled using the finite difference time domain technique, The measured insertion loss and return loss for two back-to-back transitions with a short length of microstrip line in between are better than 2.4 and –10 dB, respectively, over the frequency range of 5.1 – 6.1 GHz. The bandwidth of the transition is ~18 % at a centre frequency of 5.55 GHz.
45 citations
TL;DR: In this article, an asymmetric coplanar waveguide with finite ground plane (ASYCPWFGP) was used to achieve a return loss better than 16 dB up to 50 GHz.
Abstract: A novel balun based on an asymmetric coplanar waveguide with finite ground plane (ASYCPWFGP) to coplanar strip (CPS) transition is presented. A return loss better than 16 dB is obtained up to 50 GHz. The baluns are combined with four silicon Schottky barrier crossover diodes to yield a planar double-balanced mixer (DBM) which demonstrates an ultra-broadband performance up to 40 GHz.
41 citations
TL;DR: In this article, the authors proposed a waveguide type traveling-wave microwave power divider that is adequate for high power applications, which is composed of multiple stages of reflectionless dividing units, each having two output ports.
Abstract: We propose a new waveguide type traveling-wave microwave power divider that is adequate for high power applications. The divider is composed of multiple stages of reflectionless dividing units, each having two output ports. Design formulas for reflectionless equal-power dividing are first derived. Structural parameters for wideband design of two- to six-stage dividers are then obtained by means of numerical analyses based on an equivalent circuit. Comparison of experiments at X-band shows good qualitative agreement with the analyses. Typical measured bandwidth for relative divided powers deviation of less than /spl plusmn/0.5 dB was 2.7 GHz, and that for -20 dB return loss was more than 3.2 GHz for the four-stage (eight-way) divider. The divider presented here has excellent features; the bandwidth for equal-power dividing decreases very little and the bandwidth for low return loss increases with increasing number of the dividing stages. It also has advantages of low insertion loss and flexibility over the number of the dividing stages. >
39 citations
TL;DR: In this paper, the authors present the design, fabrication, and numerical modeling of two new uniplanar microstrip-to-coplanar strip (CPS) line transitions and a new variant of the linearly tapered slot antenna (LTSA).
Abstract: This paper presents the design, fabrication, and numerical modeling of two new uniplanar microstrip-to-coplanar strip (CPS) line transitions and a new variant of the linearly tapered slot antenna (LTSA). This new variant with an integrated uniplanar microstrip-to-coplanar strip line feed is called a V-LTSA. The advantages of these transitions in packaging and monolithic microwave integrated circuits (MMIC) integration are listed. The two transitions and the feed are modeled using finite difference time domain (FDTD) method. The overall agreement between the measured and modeled return-loss and insertion-loss characteristics of two back-to-back transitions is good. The resonance frequencies predicted by the FDTD method are within a few percentage points of the measurements. Furthermore, the V-LTSA with the feed is experimentally shown to have a wide return loss (/spl les/-10 dB) bandwidth, good radiation patterns, and low cross-polarization. The gain of the V-LTSA is 9 dB at the design frequency of 10 GHz. A proof-of-concept package to house the feed is experimentally evaluated and shown to have negligible effect on the antenna characteristics. This type of antenna readily integrates with MMIC packages in an array having a brick architecture. The V-LTSA has potential applications in phased arrays. >
37 citations
TL;DR: In this paper, a forward-coupled microstrip filter structure is presented for narrow-band applications in cellular communications, which consists of a parallel array of fully aligned half-wavelength resonators.
Abstract: A compact forward-coupled microstrip filter structure is presented for narrow-band applications in cellular communications. The structure consists of a parallel array of fully aligned half-wavelength resonators. Coupling is controlled by the spacing of the adjacent resonators, and is based on the even- and odd-mode phase velocity difference of coupled lines in a microstrip configuration. Two filter designs, based on the forward-coupled structure, were fabricated using YBa/sub 2/Cu/sub 3/O/sub 7/ (YBCO) high-temperature superconducting (HTS) thin films on LaAlO/sub 3/ substrates. One filter, a 9-pole 2.8% fractional-bandwidth YBCO filter at 900 MHz, has less than 0.27 dB insertion loss and better than 16 dB return loss. The other filter, a 5-pole 1.2% fractional bandwidth YBCO filter with 10-/spl Omega/ internal impedance at 2 GHz, has less than 0.35 dB insertion loss and better than 12 dB return loss. All designs showed excellent measured frequency response. >
34 citations
TL;DR: In this paper, the state-of-the-art single-pole double-throw (SPDT) switches exhibit insertion losses of 1.15/spl plusmn/0.15 dB over a 2-18 GHz band, which is an unprecedented performance for monolithic wideband switches incorporating on-chip bias networks.
Abstract: Two state-of-the-art monolithic GaAs PIN diode switches have been designed, fabricated and tested. These single-pole double-throw (SPDT) switches exhibit insertion losses of 1.15/spl plusmn/0.15 dB over a 2-18 GHz band, which is an unprecedented performance in loss and flatness for monolithic wideband switches incorporating on-chip bias networks. Isolation and return loss are greater than 43 dB and 12 dB, respectively, and the input port power handling is 23 dBm at 1-dB insertion loss compression. These performance characteristics were measured at a nominal bias setting of -8 V, which corresponds to 3.7 mA of series diode bias current and a total dc power consumption of 55 mW. The input power at the third-order interception is 40 dBm. The switches can handle up to 31 dBm (1.25 W) at a higher bias of -18 V and 9.3 mA. >
TL;DR: In this article, a modified dielectric cone-loaded horn is described that maintains excellent return loss and pattern symmetry over a bandwidth ratio greater than 30:1, and the mechanisms responsible for the extremely broadband operation and its application as a feed horn for a reflector antenna are discussed.
Abstract: A modified dielectric cone-loaded horn is described that maintains excellent return loss and pattern symmetry over a bandwidth ratio greater than 30:1. The mechanisms responsible for the extremely broadband operation and its application as a feed horn for a reflector antenna are discussed.
TL;DR: In this article, a novel RF switch IC using GaAs MESFET's has been developed for digital communication systems, which is composed of a three-stage SPST switch and a thin film termination resistor, which realizes a high isolation and low return loss.
Abstract: A novel RF switch IC using GaAs MESFET's has been developed for digital communication systems. The new IC is composed of a three-stage SPST switch and a thin film termination resistor, which realizes a high isolation and a low return loss. In addition, a high power handling capability and a low insertion loss are simultaneously realized with two kinds of pinch-off voltages using the orientation effect of GaAs MESFET's. According to these technologies, the excellent performance is achieved as follows: the isolation of 60 dB, the return loss of 20 dB, the 1 dB power compression of 27 dBm and the insertion loss of 1.6 dB at a frequency of 1.9 GHz with control voltages of 0/-5 V. The new switch IC contributes to a variety of communication system using high-quality digital modulation. >
01 Jan 1995
TL;DR: In this paper, a multiway switched radial power divider for use in a mobile satellite antenna-array operating in the microwave L-band is described, which features good return loss and small insertion losses over a 7% bandwidth.
Abstract: A multiway switched radial power divider for use in a mobile satellite antenna-array operating in the microwave L-band is described. The divider is designed using low-cost substrate and inexpensive switching diodes. It features good return loss and small insertion losses over a 7% bandwidth.
16 May 1995
TL;DR: In this article, the results of a planar interdigitated bandpass filter at K-band by using micromachining techniques are reported, which exhibits a return loss better than -15 dB within the passband and a 1.7 dB port-to-port insertion loss at 20.3 GHz.
Abstract: We report on the results of a state-of-the-art planar interdigitated bandpass filter at K-band by using micromachining techniques. In this design, a microwave model was first built at 850 MHz to simulate the K-band filter, and the 20 GHz micromachined filter was fabricated based on the 850 MHz microwave model. Excellent agreement has been achieved between the microwave model and the 20 GHz filter. The micromachined filter exhibits a return loss better than -15 dB within the passband and a 1.7 dB port-to-port insertion loss at 20.3 GHz. A grounded coplanar waveguide with a micromachined mouse-hole shielding structure has also been carefully examined. The grounded coplanar waveguide structure is used in the micromachined filter as the input/output feeding line and exhibits a return loss better than -20 dB up to 32 GHz. >
Patent•
27 Apr 1995
TL;DR: In this article, two impedance matching circuits were designed using broad band matching technique to expand the bandwidth for increasing the maximum receivable frequency to 1 GHz, and a 75 Ω impedance matching circuit created a 180° phase shift between the outgoing and the incoming signal for low return loss.
Abstract: An optical receiver communication system converts optical signals modulated by analog or digital waveforms to RF signals. The optical receiver contains an automatic level control circuit to adjust the electronic gain of the system accordingly across a broad bandwidth spectrum. Two impedance matching circuit are designed using broad band matching technique to expand the bandwidth for increasing the maximum receivable frequency to 1 GHz. A RLC impedance matching circuit forms a resonant combination to maintain ±1 dB fluctuation between the low-and high-frequency limits of the bandwidth, and a 75 Ω impedance matching circuit creates a 180° phase shift between the outgoing and the incoming signal for low return loss.
TL;DR: In this article, a switchable linear/circular polarised ferrite resonator antenna is investigated and it is shown that the polarisation can be switched from linear to circular by applying a static magnetic bias to the ferrite antenna.
Abstract: A switchable linear/circular polarised ferrite resonator antenna is investigated. It is shown that the polarisation can be switched from linear to circular by applying a static magnetic bias to the ferrite resonator antenna. The return loss and radiation patterns for the two polarisations are presented.
21 May 1995
TL;DR: In this article, an ultra small monolithic ceramic capacitor (MLC) has been developed for high frequency and high speed digital circuits and a microstrip fixture has been used to measure the high frequency performance accurately.
Abstract: The monolithic ceramic capacitor (MLC) is small and has good high frequency performance. It is used in various high frequency circuits for impedance matching, DC block, filter and bypass functions. For the best performance in these applications, low equivalent series resistance (ESR) and equivalent series inductance (ESL) are required. We have tested the performance of several MLC designs to find out the effect of the ESR and ESL. We have developed an ultra small capacitor that has good performance for high frequency and high speed digital circuits. In order to measure the high frequency performance accurately, we have developed a test fixture using a microstrip design. The fixture has a return loss of greater than 30 dB and an insertion loss less than 0.5 dB. The MLC is mounted on the microstrip fixture and the return loss and insertion loss are measured. A network analyzer is used to compensate for the fixture to obtain good data up to 15 GHz.
TL;DR: In this paper, a linearly polarized TEn,1mode coupler has been designed and demonstrated experimentally, and the coupling and return losses in the X-band and Ka-band couplers measured are in good agreement with theoretical predictions.
Abstract: A novel, linearly polarized TEn,1mode coupler has been designed and demonstrated experimentally. 997percnt; of the fundamental TE1,0 mode in a rectangular waveguide is converted to the TE3,1mode in a cylindrical waveguide in this coupler. The field pattern of the linearly polarized TE3,1 mode has been verified using a RF probe for an X-band coupler. The coupling and return losses in the X-band and Ka-band couplers measured are in good agreement with theoretical predictions. For the Ka-band coupler, — 25 dB of return loss and 7% 3dB bandwidth has been measured.
05 Sep 1995
TL;DR: In this article, the authors describe the temperature dependence of return loss for optical fiber connectors with refractive index-matching material and perform return loss calculations and experiments for mated flat endface plugs whose fiber endfaces had a high index layer.
Abstract: This letter describes the temperature dependence of return loss for optical fiber connectors with refractive index-matching material. We have performed return loss calculations and experiments for mated flat endface plugs whose fiber endfaces had a high index layer. We used index-matching material with a refractive index of 1.467 at 20/spl deg/C and a thermal coefficient of -2.9/spl times/10/sup -4///spl deg/C. We confirmed that almost all the connectors with a return loss of /spl ges/40 dB at 20/spl deg/C had return loss values of /spl ges/35 dB between -40/spl deg/C and 80/spl deg/C. >
TL;DR: In this paper, the authors describe the temperature dependence of return loss for optical fiber connectors with refractive index-matching material and perform return loss calculations and experiments for mated flat endface plugs whose fiber endfaces had a high index layer.
Abstract: This letter describes the temperature dependence of return loss for optical fiber connectors with refractive index-matching material. We have performed return loss calculations and experiments for mated flat endface plugs whose fiber endfaces had a high index layer. We used index-matching material with a refractive index of 1.467 at 20/spl deg/C and a thermal coefficient of -2.9/spl times/10/sup -4///spl deg/C. We confirmed that almost all the connectors with a return loss of /spl ges/40 dB at 20/spl deg/C had return loss values of /spl ges/35 dB between -40/spl deg/C and 80/spl deg/C. >
TL;DR: In this paper, a new circular waveguide-to-microstrip transition consisting of a microstrip probe inserted in a circle waveguide has been developed, which has an insertion loss of less than 0.05 dB and a return loss greater than 20 dB in the frequency range 8.72-10.66 GHz.
Abstract: A new circular waveguide-to-microstrip transition consisting of a microstrip probe inserted in a circular waveguide has been developed. Experimental results show that the transition has an insertion loss of less than 0.05 dB, and a return loss greater than 20 dB in the frequency range 8.72 – 10.66 GHz. This design can easily be scaled to other frequencies.
01 Feb 1995
TL;DR: In this paper, an octal-gate MESFET structure was employed as the voltage-variable resistors for transmitting receiving power control for a variety of digital mobile communication systems such as TDMA or CDMA.
Abstract: This GaAs variable RF attenuator IC shows extremely low distortion with a single positive control voltage. The low-distortion characteristic is realized by employing octal-gate MESFET structures as the voltage-variable resistors. The measured results at 1 GHz show insertion loss lower than 2.5 dB, maximum attenuation over 20 dB and the 3rd order intermodulation distortion (IM3) lower than -50 dBc at 0 dBm input power. The return loss is lower than -30 dB in the whole attenuation range. The present GaAs variable attenuator IC is suitable for transmitting receiving power control for a variety of digital mobile communication systems such as TDMA or CDMA.
Patent•
21 Jun 1995TL;DR: In this paper, a subscriber line interface circuit (SLIC) for a telephone system in which a 4-wire transmission path transmit signal gain and receive signal gain, and a 2-wire impedance matching correction are mutually independent is described.
Abstract: A subscriber line interface circuit (SLIC) for a telephone system in which a 4-wire transmission path transmit signal gain, a 4-wire transmission path receive signal gain, and a 2-wire impedance matching correction are mutually independent Hybrid circuitry for the SLIC includes a synthesized impedance for controlling 2-wire return loss that is grounded Impedance matching and transhybrid echo cancellation may be is carried out in an integrated circuit with the SLIC circuitry
TL;DR: In this article, an analysis and optimum method of a microstrip probe is presented, where the input impedance is derived through the dyadic Green's function in a dielectric loaded waveguide.
Abstract: An analysis and optimum method of a microstrip probe is presented. The input impedance is derived through the dyadic Green's function in a dielectric loaded waveguide. A wideband impedance match optimum process is employed to realize good return loss and insert loss of the microstrip probe. A Ka-band microstrip probe has been designed and tested. Experiment shows good coupling efficiency and return loss. © 1995 John Wiley & Sons, Inc.
01 Oct 1995
TL;DR: In this paper, the authors compared the electrical performance of wire bond/airbridges with flip-chip transitions considering the case of interconnecting a 50 Ohm microstrip or coplanar waveguide to a low impedance laser diode.
Abstract: Flip-chip technology and bond wires or airbridges are two alternative methods to connect lasers or photo diodes to the RF circuitry. With bandwidth requirements exceeding the 20GHz range, flip-chip transitions are considered to be more suitable and potentially applicable for frequencies as high as 100GHz. In this paper a study is presented comparing the electrical performance of wire bond/airbridges with that of flip-chip transitions considering the case of interconnecting a 50 Ohm microstrip or coplanar waveguide to a low impedance laser diode. Because the electrical characteristic of the flip-chip transition is dominated by the mismatch between the laser and the transmission line, it was found that in the case investigated here its performance is closer to that of an airbridge with a return loss only 6-8dB better on the average.
18 Jun 1995
TL;DR: In this article, the mixed potential integral equation (MPIE) based on the moment method is used to analyse the frequency behavior of the return loss, impedance and radiation characteristics of the annular ring slot antenna.
Abstract: In wireless communications, conformal antennas such as the slot antennas are integrated into the portable terminals. However, the energy of the annular ring slot antenna will radiate into the whole space, so a triplate structure is chosen to back-up the slot and increase the radiation efficiency into the upper half space. The mixed potential integral equation (MPIE) based on the moment method is used to analyse the the frequency behaviour of the return loss, impedance and radiation characteristics of this antenna.
TL;DR: In this article, a full-wave solution for the waveguide to microstrip transition is presented, where the exact Green's function of the transition is used in a moment method procedure.
Abstract: A “full-wave” solution is presented for the waveguide to microstrip transition. The exact Green's function of the transition is used in a moment method procedure. The behavior of the microstrip transition to a rectangular waveguide is studied with respect to the critical dimensions of the microstrip width, length and backshort location. The convergence characteristics of the full wave analysis method are investigated, along with the current distribution and the input impedance. Results given for the return loss is compared with measurements.
16 May 1995
TL;DR: In this paper, a novel concept of ferrite isolators is presented, comprised of a non-reciprocal surface wave transducer in the form of a miniature strip line mated with a finite ground plane.
Abstract: This paper presents a novel concept of ferrite isolators. The new type of isolator is comprised of a nonreciprocal surface wave transducer in the form a miniature strip line mated with a finite ground plane. The transducer is constructed on a thin YIG film grown on a GGG substrate. Since thin magnetic films can be grown on GaAs or Si, the present isolator can be built and integrated on the same chip with other passive and active devices. A 250 microns/spl times/2000 microns version of the new structure gave a 6 dB insertion loss and about 30 dB of isolation at 7.8 GHz. The return loss was more than 20 dB. >
TL;DR: In this paper, the authors presented a method for developing models that simulate return loss and insertion loss data measured over a broad band of frequencies, where the overall cable is modeled as a coaxial transmission line consisting of shunt susceptance discontinuities separated by line lengths.
Abstract: Multiple discontinuities in microwave transmission lines can cause unusual reflection and transmission loss characteristics as functions of frequency. This article presents a method for developing models that simulate return loss and insertion loss data measured over a broad band of frequencies. The overall cable is modeled as a coaxial transmission line consisting of shunt susceptance discontinuities separated by line lengths. A nonlinear least-squares fit is then performed between theoretical data (from the model) and experimental data. When this method was applied to modeling discontinuities in a slightly damaged S-band antenna cable, excellent agreement between theory and experiment was obtained over a frequency range of 1.70-2.85 GHz. >