Showing papers on "Insertion loss published in 1971"

The Design of Evanescent Mode Waveguide Bandpass Filters for a Prescribed Insertion Loss Characteristic

Abstract: A design theory for evanescent dominant mode waveguide filters is presented. The cutoff guide is represented by its equivalent /spl pi/-section network, the elements of which closely approximate lumped inductances. Resonators may be formed by introducing appropriate capacitive obstacles at suitable intervals along the guide. The filter that results is a microwave analog of lumped inductance filters with series inductance coupling, the magnitude of the series "inductance" being controlled by the separation between capacitive obstacles. The theory derives the equivalent ladder network from the low-pass prototype and is accurate up to at least 20 percent band-widths. Filters may be designed to couple into other cutoff waveguide components using the same basic principles, a propagating guide, and coaxial terminations. The filters are normally constructed in standard production waveguide and are simple and cheap to manufacture. A considerable size and weight reduction, compared with orthodox waveguide filters, is possible at the cost of a small increase in insertion loss.

Bandpass Filters for a Prescribed Insertion Loss Characteristic

Abstract: A design theory for evanescent dominant mode wave- guide filters is presented. The cutoff guide is represented by its equi- valent z-section network, the elements of which closely approximate lumped inductances. Resonators may be formed by introducing ap- propriate capacitive obstacles at suitable intervals along the guide. The filter that results is a microwave analog of lumped inductance filters with series inductance coupling, the magnitude of the series "inductance" being controlled by the separation between capacitive obstacles. The theory derives the equivalent ladder network from the low-pass prototype and is accurate up to at least 20 percent band- widths. Filters may be designed to couple into other cutoff waveguide components using the same basic principles, a propagating guide, and coaxial terminations. The filters are normally constructed in standard production waveguide and are simple and cheap to manu- facture. A considerable size and weight reduction, compared with orthodox waveguide filters, is possible at the cost of a small increase in insertion 10ss.

Rotating-waveplate optical-frequency shifting in lithium niobate

Abstract: A rotating-waveplate optical frequency shifter using lithium niobate (LiNbO 3 ) has been constructed and fully evaluated. The experimental modulator frequency shifts the incoming 6328-A light by 110 MHz, requires 15 W of drive power, and has an inherent 12-MHz bandwidth. The output beam has high spectral purity with very little power in unwanted sidebands and closely matches the TEM 00 mode of the input beam. An analysis of the effects of electrical and optical maladjustments on modulator performance shows only moderate requirements on optical and electrical alignment. Heating due to the absorbed drive power slightly degrades the modulator in agreement with a temperature analysis of the modulator. An increase in insertion loss due to diffraction of the light by acoustic waves in the LiNbO 3 crystal was observed.

Evaluation of Digitally Coded Acoustic Surface-Wave Matched Filters

Abstract: Absfracf-Acoustic surface-wave correlation filters for phaseshift-keyed (phase-coded) waveforms have been characterized. The filters were constructed using a surface-wave tapped-delayline technique that resulted in highly compact devices. Both 7- and &bit Barker sequences have been fabricated on Y-cut LiNbO, for propagation in the Z direction. For purposes of evaluation, 20- and 30-MHz center frequencies were used with information bandwidths of 1.6 and 5.0 MHz, respectively. Measurements of the time and frequency domain responses, sidelobe levels, insertion loss, temperature sensitivity, and noise performance have been made. The results obtained closely follow theoretical predictions. Although some problems exist in the control of reflections and secondary generation of the signal, the feasibility of practical acoustic surfacewave digital filters has been demonstrated.

Automatic tuning electric wave filter

Abstract: A band pass filter for use in RF transmitting or receiving apparatus comprises a plurality of resonant stages coupled through variable apertures whose areas are dependent on the tuning adjustment of the resonant stages whereby a substantially constant bandwidth and insertion loss are achieved over the tuning range. Tuning is effected by a servomechanism responsive to the conditions of phase and signal level at the input and output ports of the filter. The phase and signal level are sensed through directional couplers at the input and output ports of the filter. The couplers at the filter input and output act as matching sections, thereby minimizing losses.

Design of a New Broad-Band Isolator

Abstract: The design theory and experimental results of a proposed broad-band technique of an isolator are presented. The isolator not only has a broad-band backward loss but also a low broad-band insertion loss. The network constants and the performance are obtained in connection with the magnetic loss of ferrite, and they are confirmed by experimental data. The trial ultrawide-band isolator the performance of 20-dB isolation over the frequency band from 70 MHz to 800 MHz.

Miniature Multi-Kilowatt PIN Diode Mic Digital Phase Shifters

Abstract: A miniature high power, beryllia substrate, lumped element, PIN diode phase shifter has been developed. Design expressions are presented for two UHF models, which operate at kilowatt powers and exhibit 7% bandwidths with low insertion loss.

A Free‐Space Focused Microwave System to Determine the Complex Permittivity of Materials to Temperatures Exceeding 2000°C

Abstract: The instrumentation, the design of the free‐space focused microwave bridge system, and the technique for determining the complex permittivity of materials from ambient to 2500°C are described. The system employs a rotating disk sample which is located at the coincident focal point between two prolate spheroidal reflectors; the sample is heated on one side by oxyacetylene flames in such a manner that the microwave beam is not affected by the flames. Dynamic measurements are made of the sample insertion phase and insertion loss. A transient heat conduction analysis is used to determine the temperature profiles within the sample, and the electrical transmission data are correlated with the temperature profiles to give dielectric constant and loss tangent as functions of temperature. The relative dielectric constant and loss tangent of high purity slip‐cast fused silica (density of 1.91 g/cm3) are determined to 2500°C. The relative dielectric constant vs temperature function is a segmented line and is 3.34 at...

Rotating-Waveplate Optical-Frequency Shifting in Lithium Niobate

Abstract: dbstracf-A rotating-waveplate optical frequency shifter using lithium niobate (LiNbO,) has been constructed and fully evaluate:. The experimental modulator frequency shifts the incoming 6328-A light by 110 MHz, requires 15 W of drive power, and has an inherent 12-MHz bandwidth. The output beam has high spectral purity with very little power in unwanted sidebands and closely matches the TEMoo mode of the input beam. An analysis of the effects of electrical and optical maladjustments on modulator performance shows only moderate requirements on optical and electrical alignment. Heating due to the absorbed drive power slightly degrades the modulator in agreement with a temperature analysis of the modulator. An increase in insertion loss due to diffraction of the light by acoustic waves in the LiNbO, crystal was observed.

Wrap-around surface-wave delay lines

Abstract: Acoustic-surface-wave beams at 100 MHz have been circulated in multiple transits around the periphery of small lithiumniobate samples. A time delay of 22 µs per round-trip transit with propagation loss of 5.75 dB per round-trip transit has been observed. This has potential application to delay lines of very long delay using a helical path between input and output transducers, and to delay lines having lower insertion loss and triple-transit signals than conventional lines.

Optical transmission line elements utilizing fluorinated polymers

Abstract: Optical transmission lines constructed of fully fluorinated polymers in the amorphous state, such as fluorinated ethylene propylene, have low inherent insertion loss characteristics.

1-M W Four-Port E-Plane Junction Circulator (Correspondence)

Abstract: An S-band four-port E-plane waveguide junction circulator has been developed that has a power-handling capability of 1-MW peak and 1-kW average. Improved ferrite materials and dielectric matching techniques have resulted in a device having a high-power insertion loss of 0.5 dB and a biasing magnetic field of 400 G. The E-plane configuration lends itself to a compact lightweight circulator design having a high-power capability greater than the H-plane configuration, since RF breakdown problems are alleviated by locating the ferrite in the region of minimum RF electric field. The final device requires approximately one-tenth the amount of ferrite and permanent magnet material used in comparable differential phase-shift circulators. The size and weight are reduced by a factor of approximately 5.

Trimming of Microstrip Circuits Utilizing Microcantilever Air Gaps (Correspondence)

Abstract: A reliable method of tuning and microwave integrated circuit (MIC) line connection which has potential up to X band has been demonstrated. The method utilizes integrable fabricated microcantilever air gaps which are cold-deformed in situ to accomplish trimming. The advantages of this concept are 1) high open-circuit impedance, 2) low short-circuit insertion loss, 3) high trim resolution, 4) low line perturbation, 5) high mechanical stability, and 6) in situ fabrication with the rest of MIC circuitry.

Microwave varactor-tuned resonator for preselector

Abstract: A tunable varactor resonator has a high-Q cavity and a concentric inner probe, with one end of the concentric probe connected electrically to an eccentric probe of higher characteristic impedance in series with a varactor. Minimum insertion loss, approximately constant unloaded Q, and usability of low-Q varactor diodes are features.

Low-loss microstrip filters developed by frequency scaling

Abstract: Low-pass and band-pass microstrip filters up to 30 GHz have been built on silica substrates by photolithographic reduction of optimized low-frequency models. Scaling accuracies of 1.8 percent or better have been achieved. An insertion loss of 0.28 dB has been measured for a five-section low-pass filter with a cutoff frequency of 5.7 GHz. The insertion loss of a 12-percent band-pass filter at 8.18 GHz is 0.16 dB. Good agreement between measured and calculated losses has been obtained. Circuit dimensions are given to facilitate scaling of the low-pass and band-pass microstrip filters to other frequencies.

A New Concept for Broadbanding the Ferrite Substrate Circulator Based on Experimental Modal Analysis

Abstract: The electrical characteristics of the ferrite substrate microstrip circulator having wider magnetized region than conventional one have been studied. This work enables us to compose a compact and simplified wideband circulator without the impedance matching networks. The electric field measurement shows that the wideband characteristics are realized by the combination of the conventional n=1 mode and a nonresonant mode different but compatible to the former. A C-band version measuring 15 mm in diameter offers more than 20 dB isolation and an insertion loss less than 0.5 dB over a bandwidth of 50 percent or more with the center frequency of 6.3 GHz.

A 30-GHz Inverted-Microstrip Circulator (Correspondence)

Abstract: A 3-port inverted-microstrip circulator has been built which operates near 30 GHz with an isolation of greater than 20 dB over a 6-percent bandwidth. The circulator junction has an insertion loss of less than 0.4 dB over the band exclusive of losses in transitions used for testing the device.

Low melting point optical transmission line

Abstract: Use of material selected from classes of low-melting water-soluble glasses is found to result in low Rayleigh scattering loss. Decreased insertion loss due to this mechanism becomes significant when losses due to other mechanisms have been minimized. Reduction of ultimate insertion loss relative to the more usual insoluble high-melting glasses may justify the additional expense incurred in designing protective systems.

An Excitation System for Piston Attenuators

Abstract: The problems of mode purity and the interaction effect generally necessitate a large insertion loss in precision waveguide-below-cutoff (piston) attenuators to obtain a linear output. An attenuator excitation system, used on a precision attenuation measuring system, that reduces these problems is described. Experimental work as well as theoretical considerations are discussed and designs are presented that have produced out-put voltages of the piston attenuator greater than 1 V while still maintaining a linearity of 0.001 dB as a function of piston position. This has been accomplished by 1) operating with large input power (100-200 W), 2) development of new exciting units with improved geometry for better field excitation and utilizing water-cooled elements for high-power operation, 3) special impedance matching networks having exceptional stability with high power input, 4) use of current feedback to achieve effectively constant current excitation, and 5) a mode filter that attenuates the undesired TM 01 mode 98 dB while attenuating the desired TE 11 mode only 0.2 dB.

A 33-110-GHz Millimeter-Wave Loss Scanner

Abstract: A broad-band microwave measurement system has been designed to make insertion-loss measurements on a swept basis at millimeter wave frequencies. This instrument covers a frequency range of 33-110 GHz in three waveguide circuits, using WR-22, WR-15, and WR-10 waveguide components. Small variations in loss can be displayed and measured with a resolution of ??0.01 dB and an accuracy of ??0.08 dB while sweeping over frequency ranges as wide as 10 GHz. Insertion losses up to 60 dB can be measured with an accuracy of two percent for losses greater than 10 dB. Straighta way video detection techniques are employed. An interesting feature of the millimeter loss scanner is that random noise is averaged to insignificance and the test-set residual loss or baseline is automatically subtracted. The resultant output display is the actual insertion loss of the network under test along with any calibration lines that may be desired. This stored output can be displayed on an oscilloscope and photographed, read out on an X-Y plotter, or transmitted in either digital or analog form to a computer for further processing or analysis.

A new reciprocal phaser for use at millimeter wavelengths

Abstract: The phaser is economical to fabricate and is geometrically well suited for use in phased array antennas. A 35-GHz model is described with exhibits a 2-GHz bandwidth. The model phase may be utilized either as a 360° latching device by using flux transfer switching, or can provide up to 800° of differential phase shift with holding current bias. The nominal insertion loss of the phaser is 2 dB with a VSWR <;1.3 across its bandwidth. The measured characteristics of the phaser show good agreement with computational values.

A 40-110-GHz Precision Delay Scanner System

Abstract: A broad-band microwave measurement system has been designed to measure envelope delay distortion on a swept basis at millimeter-wave carrier frequencies. The delay scanner ultilizes the envelope phase-shift technique with a 10-MHz envelope frequency to measure delay distortion. The set operates from 40 to 110 GHz in three waveguide bands. The accuracy of delay distortion measurements is 30 ps with a resolution of 10 ps and the measurement accuracy for insertion-loss distortions is 0.08 dB with a resolution of 0.01 dB. The delay scanner meets the stated accuracy for unknowns with an insertion loss less than 10 dB. The measurement system features signal averaging for random noise reduction and baseline subtraction. The paper gives an electrical description of the delay scanner and discusses in some detail those operating principles and design approaches that were used to minimize measurement errors. Overall performance characteristics are summarized with a listing of error contributions.

Slot transmission line.

Abstract: A slot transmission line on a dielectric substrate has been proposed as an alternative to open microstrip line 'as a transmission line for microwave integrated circuits. Construction and measurement techniques suitable for this configuration are described. Experimental measurements of slot line parameters and a coaxial line-to-slot line transition from 10 MHz to 12 GHz are discussed. Insertion loss of a 2 inch length of slot line with coaxial transitions was found to be less than 5 dB from 400 MHz to 6 GHz, and the input VSVR was less than 2.0 from 1 GHz to 10 GHz.

Automatic Level Measuring System for Frequencies Between 200 Hz and 100 MHz

Abstract: An automatic level measuring system is described allowing selective voltage and voltage difference measurements with very high accuracy and high measuring speed in a frequency range of 200 Hz to 2 MHz or 10 kHz to 100 MHz. The system includes devices for measuring the reflection coefficient as well as multipoint scanners with low insertion loss and high crosstalk attenuation. All essential functions of the system can be remotely controlled and programmed. The system has a range of 150 dB. The attainable accuracy at absolute measurements is approximately 0.1 dB while the resolution for difference measurements amounts to 0.01 dB. The frequency error is smaller than 5 ?? 10-8. The results are digitally displayed and are also available as binary coded decimal (BCD) signals. To control the system and to evaluate the results (e.g., comparison with present tolerance limits, classification quality ranges), a fixed-program small computer is provided that can be fed with additional information from a punched tape or core memory. The measuring sets will most frequently be used in development, production, and maintenance areas in the field of telecommunications, but are also of general interest where high accuracy combined with high measuring speed is essential. Attainable time saving depends on the problem in question and may be of the order of 10-100.

A 90-dB Microstrip Switch on a Plastic Substrate (Correspondence)

Abstract: A single-pole double-throw (SPDT) microstrip switch has been designed on a plastic (polyolefin) substrate to switch two 10-W CW carriers into a common load over the frequency range 1.7 to 2.3 GHz. No tuning adjustments are used over this 30-percent bandwidth to obtain a 90-dB minimum isolation, a 23-dB minimum return loss, and a 1-dB maximum insertion loss. Units now in production typically have a 0.6-dB insertion loss, a 26-dB return loss, and isolation levels of 105/spl plus mn/5 dB.

A 90 DB Microstrip Switch on a Plastic Substrate

Abstract: A SPDT microstrip switch has been designed on a plastic (polyolefin) substrate to switch two 10 watt cw carriers into a common load over the frequency range 1.7 to 2.3 GHz. No tuning adjustments are used over this 30% bandwidth to obtain a 90 dB minimum isolation, a 23 dB minimum return loss, and a one dB maximum insertion loss. Units now in production typically have a .6 dB insertion loss, a 26 dB return loss and isolation levels of 105/spl plusmn/5 dB.

Circular TE01 periodic waveguide as delay line for pulse compression

Abstract: An iris-loaded circular waveguide 1.3 m long, operating in the low-loss circular TE01 mode, produced 500 ns differential delay for a 50 MHz bandwidth at X band. The insertion loss was 2.2 dB.

A Fast 3-mm Ferrite Switch (Correspondence)

Abstract: A tetrahedral waveguide junction type of switch has been developed for use in the millimeter region. The design employs a permanent magnet such that the switch operates in the transmission state without any external dc power. By applying a current pulse it switches from the transmission state to the reflective state in 400 ns and back to the transmission state in less than 200 ns. Over the frequency range of 95.5 to 97.2 GHz the switch exhibits a maximum insertion loss of 1.0 dB and a minimum isolation of 25 dB.