Showing papers on "Insertion loss published in 1978"
TL;DR: In this article, a design method for acoustic thin disk transducers with high efficiency, broad bandwidth, and good impulse response is presented, based on the use of quarter-wave matching layers between the piezoelectric material and the acoustic load.
Abstract: A design method for acoustic thin disk transducers with high efficiency, broad bandwidth, and good impulse response is presented. This method is based on the use of quarter-wave matching layers between the piezoelectric material and the acoustic load. As is made evident using the transmission line model of Krimholtz, Leedom, and Matthaei, the finite thickness of the piezoelectric material must be taken into account in the matching layer design. Criteria for optimum broad-band transducer designs with a given piezoelectric material are developed which show the importance of a high electromechanical coupling coefficient. A method for obtaining Gaussian shaped passbands, necessary for optimum impulse response, is also shown. Several transducers have been built to illustrate this design approach with excellent agreement between theory and experiment. One such transducer has 3.2 dB round trip insertion loss and one octave bandwidth.
458 citations
01 Mar 1978
118 citations
TL;DR: In this paper, optical insertion losses in embedded strip waveguides fabricated in LiNbO3 by Ti diffusion have been examined at a 0.633μm wavelength, taking into account resultant near field patterns.
Abstract: Optical insertion losses in embedded strip waveguides fabricated in LiNbO3 by Ti diffusion have been examined at a 0.633‐μm wavelength, taking into account resultant near‐field patterns. It is confirmed that the main factors influencing optical insertion losses are radiation loss by the deficient refractive‐index change of a waveguide, scattering loss by insufficient diffused residual titanium oxide film on a waveguide, and coupling loss between a waveguide and a fiber. A diffusion condition for making a low‐loss waveguide is presented, although suppression of lateral diffusion is necessary to achieve further insertion‐loss reduction.
106 citations
01 Jan 1978
TL;DR: In this article, a design method for acoustic thin disk transducers with high efficiency, broad bandwidth, and good impulse response is presented, based on the use of quarter-wave matching layers between the piezoelectric material and the acoustic load.
Abstract: Absrruct-A design method for acoustic thin disk transducers with high efficiency, broad bandwidth, and good impulse response is presented. This method is based on the use of quarter-wave matching layers between the piezoelectric material and the acoustic load. As is made evident using the transmission line model of Krimholtz, Leedom, and Matthaei, the finite thickness of the piezoelectric material must be taken into account in the matching layer design. Criteria for optimum broad-band transducer designs with a given piezoelectric material are developed which show the importance of a high electromechanical coupling coefficient. A method for obtaining Gaussian shaped passbands, necessary for optimum impulse response, is also shown. Several transducers have been built to illustrate this design approach with excellent agreement between theory and experiment. One such transducer has 3.2 dB round trip insertion loss and one octave bandwidth.
94 citations
TL;DR: In this paper, a modified transverse electromagnetic TEM cell with expanded bandwidth for use in accurately characterizing electromagnetic interference (EMI) fields within a shielded environment is presented. Butler et al. used the cell to evaluate the radiated emissions from a common electronic module (microprocessor timing circuit).
Abstract: This paper discusses the development of a modified (absorber-loaded) transverse electromagnetic TEM cell with expanded bandwidth for use in accurately characterizing electromagnetic interference (EMI) fields within a shielded environment. The cell is analyzed experimentally, both before and after the modification, to determine its radio-frequency (RF) characteristics, both as an RF transmission line and as an electromagnetic (EM) field simulator or detector. Comparative measurements are given to show the performance of the modified versus the unmodified cell in parameters such as voltage standing-wave ratio (VSWR), insertion loss, test-field uniformity, and reverse-coupling characteristics. The results of these measurements indicate an approximate two-fold increase in the upper useful frequency of the modified cell. An example of using the cell to evaluate the radiated emissions from a common electronic module (microprocessor timing circuit) is given. Finally, the technique of absorber loading is extended to larger cells, specifically a 3- × 3- × 6-m cell.
64 citations
01 Jan 1978
TL;DR: A power combining technique for GaAs FET amplifiers using a 12-way divider-combiner has demonstrated a 31% 1dB bandwidth with an insertion loss of 0.25dB and a CW output power of 4.4W at 8.5GHz.
Abstract: A power combining technique for GaAs FET amplifiers will be presented. The approach, using a 12-way divider-combiner, has demonstrated a 31% 1dB bandwidth with an insertion loss of 0.25dB and a CW output power of 4.4W at 8.5GHz.
53 citations
TL;DR: In this article, an optical wavelength division multiplexer for multimode fiber transmission systems was demonstrated at λ ~ 1.1 µm using a blazed reflection grating and a graded-refractive-index (g.r.i.n.) lens.
Abstract: An optical wavelength-division multiplexer, for multimode fibre transmission systems, has been demonstrated at λ ~ 1.1 μm. The device used a blazed reflection grating and a graded-refractive-index (g.r.i.n.) lens. The spectral response was measured using a tunable fibre Raman oscillator. The insertion loss was ≤2.6 dB, and the crosstalk level was ≤−29 dB. The device is compared to other multiplexers.
51 citations
TL;DR: In this paper, a 3 dB coupler was fabricated using two partially polished fibres which were in contact with each polished portion, and the excess insertion loss and the directivity of this coupler were measured to be 0.36 dB and 47.0 dB, respectively.
Abstract: A 3 dB coupler was fabricated using two partially polished fibres which were in contact with each polished portion. The excess insertion loss and the directivity of this coupler are measured to be 0.36 dB and 47.0 dB, respectively.
45 citations
27 Jun 1978
TL;DR: In this paper, it was shown that no spurious response in the octave band, relative bandwidth of 6 % or more, and frequency stability of 10 ppm/spl deg/c or less can be realized for these filters.
Abstract: New types of miniaturized bandpass filters have been constructed by using TM/sub 010/ dominant mode of a shielded dielectric rod resonator. The next higher order mode exists at an octave frequency band above the TM/sub 010/ mode. It is shown that no spurious response in the octave band, relative bandwidth of 6 % or more, and frequency stability of 10 ppm//spl deg/c or less can be realized for these filters. The insertion loss corresponding to the measured unloaded Q of 2800 at 6 GHz is expected.
TL;DR: In this paper, a new type of 100kW waveguide Y-junction circulator is realized by dividing the junction of the circulator into four equal unit junctions in a so-called "multilayer structure," which is water-cooled easily.
Abstract: A junction circulator appears inferior in average power-handling capability, although it is compact and light-weight and has good performance A new type of 100-kW CW waveguide Y-junction circulator is realized by dividing the junction of the circulator into four equal unit junctions in a so-called "multilayer structure," which is water-cooled easily This circulator has an insertion loss of 018 dB and an isolation of 20 dB, and it is compact and economical to build The design of 30- and 100-kW CW waveguide Y-junction circulators is presented in this paper, which discusses determination of ferrite dimensions and air gap, considers heat generation in the ferrite, and the influence of dc magnetic-field distribution on its performance The ferrite dimensions and air gap are determined very easily by using this design method, and these have been confirmed by experiment It was found that a uniform distribution of internal dc magnetic fieId, obtained by considering the demagnetizing dc magnetic field, gives optimum performance This is a significant design factor for high-power circulators which require minimum insertion loss
TL;DR: The switch uses a V-grooved connecting device suitable for a large switch, which is desirable for an optical switching system, and the insertion condition, which realizes stable connection and high durability is discussed.
Abstract: The switch uses a V-grooved connecting device The mechanism is suitable for a large switch, which is desirable for an optical switching system A moving fiber is inserted into one of the radially arranged V grooves using the elastic bending force as the drive current The insertion condition, which realizes stable connection and high durability, is discussed Switch structure and experimental results are described Insertion loss was 033 dB, and the variation in transmissivity was 3%
TL;DR: In this article, a compact Faraday-rotation 4-port circulator was developed for the near-infrared region, which consists of an yttrium-iron-garnet Faraday rotator, biased by two permanent magnets, and two Glan-Taylor prisms.
Abstract: A compact Faraday-rotation 4-port circulator was developed for the near-infrared region. This circulator consists of an yttrium-iron-garnet Faraday rotator, biased by two permanent magnets, and two Glan-Taylor prisms. Insertion losses of 2.7–3.2 dB and isolation ratios of 13–28 dB among non-reciprocal ports were obtained at 1.15μm wavelength.
TL;DR: In this article, an 8.5-9.6-GHz 1-MW differential phase shift circulator with an insertion loss of less than 0.20 dB was developed, which leads to an exceptionally low loss device at both small and large signal levels.
Abstract: Instability in high peak power ferrite devices is usually avoided by either widening the spinwave linewidth to move the onset of the subsidiary resonance above the specification of the device, or by using a value of magnetic field below that at which the peak in the subsidiary resonance occurs. A third way to prevent this instability altogether is by adjusting the direct field and material magnetization to prohibit the frequency relation between the microwave signal and the spinwaves. This approach leads to an exceptionally low loss device at both small and large signal levels. The paper describes the experimental development of an 8.5-9.6-GHz 1-MW differential phase shift circulator biased in this way with an insertion loss of less than 0.20 dB.
TL;DR: In this paper, a low insertion loss (LOW) delay line with low passband ripple (2 dB) was proposed to terminate unwanted waves within the yttrium iron garnet (YIG) samples.
Abstract: Magnetostatic waves (MSW) propagating in low line‐width (ΔH<0.5 Oe) yttrium iron garnet (YIG) films grown by liquid phase epitaxy (LPE) constitute a potential basis for analog signal processing directly at microwave frequencies (1–20 GHz). MSW device techniques are complementary to those utilized in surface acoustic wave (SAW) devices at VHF/UHF. A necessary prerequisite for a high performance MSW analog signal processing technology is a low insertion loss (<20 dB) delay line with low passband ripple (<2 dB). Shorted, narrow microstrip transducers readily provide the low insertion loss; thus, the major problem is that of terminating unwanted waves within the YIG samples. Unterminated magnetostatic forward volume wave (MSFVW) delay lines can easily have passband ripple in excess of 20 dB. By measuring the frequency periodicities of these ripples in the passband and the corresponding group delays, all sources of reflection have been identified. Terminations consisting of magnetic recording tape, ferrite pow...
TL;DR: In this article, a low drive-voltage optical modulator using a Ti-diffused UNbO3 optical waveguide has been fabricated, and the halfwave voltage, 3 dB bandwidth, optical insertion loss and extinction ratio were 3·8 V, 850 MHz, 10 dB and 13 dB, respectively.
Abstract: A low drive-voltage optical modulator using a Ti-diffused UNbO3 optical waveguide has been fabricated. Stabilization against ambient temperature change was realized by using a miniature halfwave plate. The halfwave voltage, 3 dB bandwidth, optical insertion loss and extinction ratio were 3·8 V (at 1·06μm wavelength), 850 MHz, 10 dB and 13 dB, respectively. A reduction scheme for the optical absorption caused by metallic electrodes, and an analysis of the modulator high frequency response are also reported.
TL;DR: In this article, a new configuration with a grooved waveguide was proposed and analyzed for the purpose of improving the performance of the non-reciprocal remanence ferrite phase shifter.
Abstract: For the purpose of improving the performance charasteristics of the nonreciprocal remanence ferrite phase shifter, a new configuration with a grooved waveguide is proposed and analyzed. Some results calculated as functions of dielectric and ferrite thickness, waveguide dimensions, and frequency are shown and compared as being in good agreement with experiments at the X band. The figure of merit (differential phase shift per insertion loss) and the handling power of the proposed phase shifter are discussed in comparison with those of the conventional waveguide geometry.
Patent•
31 May 1978TL;DR: In this paper, a first central transducer, a second transducers and a third transducers are disposed on one surface of a piezoelectric substrate in such a manner that the second and the third Transducers are in the direction of propagation (X-direction) of surface acoustic waves launched by the first transducers.
Abstract: To obtain low insertion loss and low TTE level, a first central transducer, a second transducer and a third transducer are disposed on one surface of a piezoelectric substrate in such a manner that the second and the third transducers are in the direction of propagation (X-direction) of surface acoustic waves launched by the first transducer and the distance between center lines of the first and the second transducers and also the distance between the center lines of the first and the third transducers vary along the Y-direction perpendicular to the X-direction.
01 Jan 1978
TL;DR: In this paper, the authors describe the successful operation of a buried heterojunction electroabsorption modulator, fabricated from AlyGa1−yAs 1−xSbx/GaAs1−x′SbX′, which is particularly well suited for use with narrow spectral width sources such as the Nd :
Abstract: We describe the successful operation of a buried heterojunction electroabsorption modulator. This modulator, fabricated from AlyGa1−yAs1−xSbx/GaAs1−x′Sbx′, is particularly well suited for use with narrow spectral width sources such as the Nd : YAG fiber lasers. The GaAs1−x′Sbx′ crystal composition can be adjusted to permit operation in the wavelength range 0.9–1.2 μm. At 1.06 μm we have obtained an extinction ratio of 13 dB and a projected insertion loss of 4.0 dB. The low device capacitance permits operation at greater than 900 MHz.
27 Jun 1978
TL;DR: In this article, the capacitive coupled transmission line band pass filters were miniaturized about from 1/4 to 1/6 of size of the conventional filters without increasing insertion loss by using ceramics which has high dielectric constant and excellent temperature stability.
Abstract: The capacitive coupled transmission line band pass filters were miniaturized about from 1/4 to 1/6 of size of the conventional filters without increasing insertion loss by using ceramics which has high dielectric constant and excellent temperature stability (within /spl plusmn/2 PPM//spl deg/C). The spurious response of the second and the third harmonics were clearly shifted from multiples of the dominant mode by using "composite TEM cavity resonator." The new band pass filters are applied to L or S band of frequency.
TL;DR: In this article, the insertion loss is derived in terms of generator impedance, load impedance, and filter open-circuit and short circuit impedances, and a simplified approximate expression for insertion loss which is applicable in a filter attenuation band is presented.
Abstract: Insertion loss is derived in terms of generator impedance, load impedance, and filter open-circuit and short-circuit impedances. This expression contains a difference term which places great weight on the accuracy with which filter impedances are measured. It is shown that the use of this difference term can be avoided by introducing the filter insertion loss in a circuit with known generator and load impedances. The resulting exact expression contains terms which are easily measurable with sufficient accuracy to provide reliable insertionloss values for the filter for any combination of generator and load impedances. Also shown is a simplified approximate expression for insertion loss which is applicable in a filter attenuation band. A discussion of experimental verification of the expressions is followed by curves showing application of the approximate insertion-loss expression to a particular filter.
Patent•
18 Sep 1978
TL;DR: In this paper, the authors propose a broadband isolator design wherein the amount of insertion loss may be traded for bandwidth and possibly reduced circuit complexity, and employ two windings or conductors with the neutralizing element connected across the input-output terminals, or may have a third winding placed to bisect the angle between the other windings and the neutralizer coupled across this third winding.
Abstract: A broadband isolator design wherein the amount of insertion loss may be traded for bandwidth and possibly reduced circuit complexity. The isolator may employ two windings or conductors with the neutralizing element connected across the input-output terminals, or may have a third winding placed to bisect the angle between the other windings and the neutralizing element coupled across this third winding. The angle between the windings and the isolator interconnection determine the specific bandwidth and insertion loss.
Patent•
23 Feb 1978
TL;DR: In this paper, the diameter of the spot circular metal film was set to 1/2 length of the elastic surface wave or more, and the reflection coefficient was decided regardless of the film thickness.
Abstract: PURPOSE:To simplify manufacture of the delay line or the like by setting the diameter of the spot circular metal film more than the length of the elastic surface wave and then setting the thickness of the film regardless of the insertion loss in case the film is used at the lower frequency regions CONSTITUTION:Input and output converters 12 and 13 made of the roller-screen type electrodes are installed in parallel on piezoelectric substrate 11, and furthermore reflectors 14-24 formed with the metal film made of the spot circular metal rows are provided on substrate 11 in opposition to converters 12 and 13 Then a linear- symmetric distribution to line O1-O2 is given to the reflection grids provided to converters 12 and 13 each centering on axis O1-O2 and in the propagation direction of the elastic surface wave excited by converter 12 of the input side Then the diameter of the circular metal film is set to 1/2 length of the elastic surface wave or more, and the reflection coefficient is decided regardless of the film thickness Thus the insertion loss can be minimized for the film when used at the lower frequency regions, facillitating the manufacture of the delay line or the like
TL;DR: In this paper, a 50kW CW differential phase shift circulator at 2450 MHz has been developed, which is useful for protecting the microwave source of a high-power system from reflected power.
Abstract: A 50-kW CW differential phase-shift circulator at 2450 MHz has been developed. Its insertion loss and isolation are 0.18 dB and 20 dB, respectively, over a bandwidth of 25 MHz at 2450 MHz. It is useful for protecting the microwave source of a high-power system from reflected power. The design and experimental results of the circulator are presented.
TL;DR: The construction of a working prototype data bus using mirror terminals demonstrates the feasibility of such systems for use in optical communications at the present state of the art.
Abstract: A prototype fail-safe optical data bus utilizing active LiTaO3 electrooptic mirror terminals has been constructed and tested. Features of the system include (1) a single optical source; (2) an optical insertion loss of less than 6 dB and a tapoff ratio of 13 dB for the mirror terminals in the fail-safe mode; (3) compatibility with commercially available LED sources, P-I-N photodiode detectors, and step-index multimode monofibers; (4) remote terminal modulation depth approaching 50% for 100 V applied; and (5) the use of a pulse transformer technique which allows the required electrooptic modulation voltages to be obtained from a 5-V electrical supply. The construction of a working prototype data bus using mirror terminals demonstrates the feasibility of such systems for use in optical communications at the present state of the art.