Showing papers on "Return loss published in 1989"

SC-type single-mode optical fiber connectors

Abstract: SC-type single-mode optical fiber connectors specifically developed for subscriber loop networks are discussed. The properties and design of precision zirconia ceramic ferrules which have been found to be ideal for high-performance, low-cost single-mode optical fiber connectors are described. A design approach featuring a plastic-molded rectangular connector housing using a push-pull coupling mechanism which has also been found to be suitable for durable, compact, and low-cost connectors is presented. SC connectors used with 10/125 single-mode fibers exhibit insertion loss of 0.06 dB and return loss of 38.6 dB, with no degradation during and after mechanical and environmental tests. To realize higher packaging density, duplex-ferrule connectors, quadruple-ferrule connectors and optical attenuators have also been developed on the basis of the SC connector design. >

Transmission characteristics of a power line used for data communications at high frequencies

Abstract: The transmission characteristics of an installed power line used for data communication, and of a model of this actual line, were measured over the frequency range of 10 kHz-50 MHz. It was found that impedance characteristics were not greatly influenced by the working loads at high frequencies, but changed drastically at lower frequencies. For frequencies of less than 100 MHz, the transmission loss did not increase significantly with frequency. The effect of the length of the connections and variation in load impedance were both studied. It was found that for frequencies above 100 MHz, attenuation loss in the power line is divided into losses due to attenuation constant of the line and the loss occurring at wire connections located between the various wires in the wall sockets. The latter loss is proportional to the number of connections. When the transmission loss was measured by opening and closing the wire connections, the fluctuation in the loss was found to be smaller at frequencies above 1 MHz than at lower ones. The transmission loss at the higher frequency shows only fairly slight fluctuations to variations in working load on the power line. The intensity of the noise power spectrum shows a decrease of -40 B/decade. This degradation rate in the noise spectrum is greater than the rate of increase in transmission loss. The increasing transmission loss can be sufficiently compensated by amplification at the receiving end, but it is possible to keep the amplified noise below the level of disturbance. >

Transmission line switch

Abstract: A transmission line switch allows a single output line (3) to be switched to one of two or more input lines (1,2) to which it is permanently connected at a common junction (4). Each input line (1,2) has an associated amplifier stage (10) which can be biased in a normal high gain (`on`) state, or in an isolation (`off`) state. Suitable biasing in the `off` state ensures that the amplifier stage output presents a low impedance to its own input line, the length (L) of which is chosen to reflect a high impedance at the junction (4) with the other lines. Correct design enables the return loss and insertion loss of the `on` path to be kept to low values while simultaneously offering a high insertion loss to the `off` path signals.

Slot—coupled directional couplers on a both—sided substrate MIC and their applications

Abstract: A slot-coupled directional coupler is proposed and analyzed. In the slot-coupled directional coupler, microstrip lines set on both sides of a common ground plane are coupled through a slot in the common ground plane. This coupler can easily realize a tight coupling such as 3 dB with a small physical size. This paper shows that it is possible to form a planar multiport directional coupler with 2n (n: integer) input or output ports without line crossings by combining slot-coupled directional couplers. Using such a planar multiport slot-coupled directional coupler, a multiport power amplifier and a BMN (Butler matrix network) can easily be formed in a small physical size. The 3-dB slot-coupled directional coupler fabricated for trial has a coupling of 3.2 ± 0.2 dB, a return loss of more than 25 dB, and an isolation of more than 28 dB in the frequency range of fO ±20 percent (fO = 1.5 GHz). These measured values agreed well with computed data.

Microwave properties of the talc filled polypropylene

Abstract: A microwave bench operating in the frequency range 8–12 GHz (X-band) was used to investigate some of the electrical characteristics of the talc filled polypropylene composite. The impedance, return loss, and insertion loss are measured as a function of frequency in the X-band range. It was found that electromagnetic waves interact with the material via the impurities, inclusions and voids existing in the bulk composite. The impedance, return loss and insertion loss show relatively low frequency dependence. Also, the return loss and the impedance exhibit a resonance behaviour at 11.91 GHz. The results suggest that this composite material could be used in some microwave applications.

Rigorous Field Theory Design of Compact and Lightweight Broadband Diplexers for Satellite Communication Systems

Abstract: A new design of compact, lightweight, broad-band and low-insertion-loss diplexers for satellite conununication systems is introduced utilizing E-plane corrugated and below-cutoff waveguide filters in the septate waveguide sections of E-plane furcated power dividers with asymmetrical transformer heights. The rigorous optimization technique comprises the complete component, including all discontinuities as well as the higher order mode interaction between them. Results are given for a computer optimized design exmnple for a minimum input port return loss of about 22 dB over the transmit (3.7 - 4.3 GHz) and receive (5.83 - 6.5 GHz) frequency band. The theory is verified at a R- 48 waveguide diplexer example which was milled from a solid block.

High isolation 1-20 GHz MMIC switches with on-chip drivers

Abstract: The design, fabrication, and performance of monolithic microwave integrated circuit single-pole single-throw (MMIC SPST) and single-pole double-throw (SPDT) switches with on-chip transistor-transistor logic (TTL) compatible drivers is presented. Both switch types cover 1-20 GHz, operate from a single +10 to +12 V power supply and commute in less than 15 ns. Both have at least -12 dB return loss at all ports and handle +22 dBm signal levels. The SPST switch has an insertion loss of 2.5 dB and >50 dB isolation. The SPDT switch's insertion loss is 2.7 dB with 49 dB isolation. The switches require only external DC blocking capacitors to set the lower end of their useful bandwidth. The excellent isolation achieved by these switches is principally attributable to the design of the series and shunt FETs used in their realization. >

Novel multioctave MMIC active isolator (1-20 GHz)

Abstract: We present a multioctave MMIC active isolator (1–20 GHz) requiring only two fidd-effect transistors (MESFETs or HEMTs) and exhibiting more than 20 dB input return loss, 18 dB output return loss with more than 20 dB reverse loss and less than 9 dB transmission loss.

Transmitted power variations in single-mode fiber joints with obliquely polished endfaces

Abstract: An experimental and theoretical study of multiple-beam interference effects at oblique endface airgap joints, with endfaces oriented parallel to each other, is discussed. It was found that although excellent return loss performance can be obtained by using such joints, large variations in the transmitted power can result in small changes in endface separation. Compared to the case of nonoblique endfaces, endface separation between the successive fringes in oblique endfaces increases by a factor which depends on the oblique angle and the refractive index of the gap material. >

Estimation of fiber loss and return signal power

Abstract: A method of determining estimates of fiber loss and return signal power for an optical fiber from a return signal uses a polynomial fit with data samples representing the return signal. From the polynomial fit an estimated fiber loss value is determined. The estimated return signal power is computed using a function of the estimated fiber loss value.

Performance of low loss, high speed interconnects for multi-GHz digital systems

Abstract: Preliminary frequency-, time-, and digital-domain testing and electromagnetic simulations indicate that the striplines and microstrip lines of Honeywell's thin-film multilayer (TFML) technology are suitable for high-performance digital systems that require operation at frequencies greater than 1 GHz. The return loss was typically -20 dB, which indicates the ability to design and fabricate controlled impedance lines with Honeywell's TFML technology. The 1- and 2-GHz digital-domain test measurements did not appear to be affected significantly by the reflections. The insertion loss of approximately -2.5 dB/in. at 9 GHz is acceptable for relatively short signal interconnect lines which, in any event, are required to minimize interchip propagation delays in a functioning system. Predictions from the Mayo electromagnetic modeling package show excellent agreement with measured signal and crosstalk waveforms. The crosstalk between adjacent lines is less than -20 dB even when the coupled line length is very long (>6 in.). Vias and via pads show negligible effects on insertion and return losses up to a frequency of 9 GHz. Large impedance mismatches severely affect the return losses, and therefore should be avoided. Stubs in the interconnect must be kept smaller than 1/4 of the smallest wavelength within the signal bandwidth. >

Performance characteristics of thin film multilayer interconnects in the 1-10 GHz frequency range

Abstract: Multichip packaging approaches that provide short chip-to-chip interconnects are required to utilize fully the high-speed potential of silicon ECL (emitter-coupled logic) and GaAs ICs. To maintain signal fidelity at gigahertz clock speeds, interconnects must be designed as impedance-controlled transmission lines with proper concern for discontinuities, crosstalk, and attenuation. At present, there is very little quantitative data for frequencies greater than 1 GHz on the effect of the typical elements encountered in hybrid and multichip packaging. Initial results from a program to develop much of this data are presented. The platform chosen to quantify high-frequency multichip packaging effects is a copper/polyimide-based thin-film multilayer (TFML) technology. Measurements of return loss, insertion loss, and characteristic impedance of interconnects of various lengths were made up to 9.045 GHz. Signal attenuation and crosstalk of 1- and 2-GHz digital signals were measured and simulated. In general, the loss and crosstalk values obtained were low enough to permit the transmission of gigahertz digital signals over typical interconnect lengths encountered in a multichip module. >

Integrated Input Circuit for Satellite Converter

Abstract: This paper describes an integrated input circuit for the receiver converter of the German Telecommunication Satellite, Kopernikus, which operates in two frequency bands for two orthogonally linear polarized signals. The input circuit consists of antenna feed horn, band-pass filter and ortho-mode transducer and has been realized in Integrating Waveguide Technology. This circuit is simple and cheap in mass-production and has shown to provide, in two destinated frequency bands 11.45 - 11.70 GHz and 12.50 - 12.75 GHz, good performance, i.e. crosspolarization isolation better than 30 dB, return loss higher than 15 dB, insertion loss lower than 0.65 dB and width of the radiation Batterns (at ?10 dB level) in both orthogonal planes about 140. The parameters are not sensitive over wide temperature range.

A High Frequency Low Noise Acoustic STW VCO

Abstract: A voltage controlled oscillator (VCO) at 2.65 GHz has been developed using acoustic surface transverse wave (STW) delay lines operating at the fifth harmonic as the frequency controlling element. A filter with three transducers has been designed. The STW filter also serves as the oscillator output coupler. Compared to a microstrip coupler, the spectral characteristic of the oscillator is strongly improved due to the high selectivity of the transducer type coupler. The Q value and the untuned insertion loss of the filter were 3600 and 30 dB, respectively. A very thin metallization of only 25 nm aluminum was used for the STW filter. Excellent phase noise data have been measured. A single-sideband phase noise to carrier ratio of ?93 dBc/Hz at 1 kHz and ?63 dBc/Hz at 100 Hz was attained. As a phase shifter, a GaAs varactor diode circuit is used. Tuning range and output power of the oscillator were ± 375 kHz and 3 dBm, respectively. The load pulling (frequency stability) is ± 3.5 kHz at 12 dB return loss. Attenuation of harmonics is higher than 44 dB referred to the carrier.

Ultra-broadband lossy match amplifiers

Abstract: The authors describe the design, fabrication, and performance of a three-stage lossy match amplifier with a gain of 8.0+or-0.6 dB and a return loss of better than 9 dB over the 2- to 32-GHz band. By using a novel m-derived low-pass network with cutoff frequency of greater than square root 2 times as high as that of a conventional network, the ultrabroadband lossy match amplifier has achieved a high gain-bandwidth product. The advantage of this novel network is that the gain can be increased without lowering the bandwidth by increasing the interstage network impedance of the lossy match amplifier. >

2/4 wire conversion circuit

Abstract: PURPOSE:To reduce the insertion loss and to facilitate the design and manufacture by setting a transfer function of a termination impedance synthesis section and an insertion loss correction section in response to the two wire line impedance and setting and fixing the transfer function of a reflection cancel section according to the two transfer functions. CONSTITUTION:The transfer functions HZ, HO of the termination impedance synthesis section 3 and the insertion loss correction section 4 are set in response to the impedance ZL of the two wire line impedance. Then the transfer function HB of the reflection cancel section 5 is set and fixed according to the two transfer functions HZ, HO. Thus, the deterioration in the return loss characteristic is prevented, the insertion loss is reduced, the variable part is reduced be fixing the transfer function HB and the design and manufacture are facilitated.

An S and C Band GaAs Single Chip Combined Phase Shifter and Amplifier

Abstract: This paper describes the design and measured results of a multifunction MMIC designed for phased array applications. The circuit has a six bit switched filter phase shifter, five amplifiers and two SPDT transmit receive routing switches. The band of operation is 2 - 6GHz and the chip size is 5.8mm × 1.8mm (area ? 10.5 mm2). The maximum measured gain is 22dB and the worst case measured input return loss is 14dB. It is believed that the multifunction MMIC to be described is one of the worlds most complex working analogue GaAs MMIC's.

Ultrabroadband amplifiers using hybrid circuits

Abstract: This paper describes the design, fabrication, and performance of hybrid distributed and lossy-match amplifiers having a wide bandwidth. Two types of novel m-derived low-pass networks with a cutoff frequency of 22 or greater than that of a conventional m-derived low-pass network is proposed in order to achieve a wide bandwidth of the hybrid distributed and lossy-match amplifiers. The distributed amplifier exhibits a gain of 6.0 ± 0.6 dB and a return loss of better than 10 dB over the 2 to 26.5 GHz band by using a novel m-derived low-pass network with a cutoff frequency 22 times as high as that of a conventional network. On the other hand, the three-stage lossy-match amplifier shows a gain of 8.0 ± 0.6 dB and a return loss of better than 9 dB across the 2 to 32 GHz band by using a noval m-derived low-pass network with a cutoff frequency greater than 2 times as high as that of a conventional network.

Trunk line circuit

Abstract: PURPOSE:To improve characteristics of sidetone and return loss by providing a circuit which forms a DC loop to a telephone line by an artificial inductance and a circuit which controls the variance of the DC resistance value of said circuit CONSTITUTION:The loop current from the telephone line flows to the telephone line through a diode D3 or D4, a make contact M of a relay contact RY1, a common contact C, the collector and the emitter of a transistor TR 2, a resistance R8, and a diode D2 or D1 When the DC resistance value of a DC loop forming circuit 2 is changed by an AC signal of a voice or the like, this change is controlled by a feedback circuit 3 connected to the DC loop forming circuit 2 to stabilize the impedance of the DC loop forming circuit 2 Thus, characteristics of return loss and sidetone are improved, and an inexpensive exchange is realized because the DC loop forming circuit 2 consists of inexpensive parts such as the TR 2