Showing papers on "Balun published in 1995"

Three-dimensional passive circuit technology for ultra-compact MMICs

Abstract: A novel passive circuit technology of a three-dimensional (3-D) metal-insulator structure is developed for ultra-compact MMICs. By combining vertical passive elements, such as a wall-like microwire for shielding or coupling, and a pillar-like via connection with multilayer passive circuits, a 3-D passive circuit structure is formed to implement highly dense and more functional MMICs. O/sub 2//He RIE for forming trenches and holes in a thick polyimide insulator, low-current electroplating for forming gold metal sidewalls in the trenches or holes, and ion-milling with a WSiN stopper layer for patterning the gold metal are used to produce such a structure. The complete 3-D structure provides miniature microstrip lines effectively shielded with a vertical metal-wall, a miniature balun with low-loss vertical wall-like microwires, and inverted microstrip lines jointed with pillar-like vias through a thick polyimide layer. This technology stages next-generation ultra-compact MMICs by producing various functional passive circuits in a very small area.

New uniplanar transitions for circuit and antenna applications

Abstract: New uniplanar microstrip-to-slotline, microstrip-to-coplanar strips (PS) and microstrip-to-coplanar waveguide (CPW) transitions for MIC/MMIC and slotline antennas for phased array applications are described. Such transitions are compact and suitable to be used in an open environment inside a package or a multichip module. The transitions share the concept of using a balun which consists of two microstrip lines connected to a slotline through a pair of coupled microstrips. In this paper, the transitions are studied theoretically using the Finite Difference Time Domain (FDTD) technique and measured experimentally using an HP8510C Network Analyzer. For a back-to-back microstrip-to-slotline transition, an insertion loss of less than 1.3 dB per transition is achieved over a 49% bandwidth with a minimum of 0.6 dB around the design frequency.

Balun design for uniplanar broad band double balanced mixer

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.

A GaAs single balanced mixer MMIC with built-in active balun for personal communication systems

Abstract: A GaAs single balanced mixer IC with built-in active baluns for IF and LO inputs has been developed. The present mixer achieved the conversion gain of 16 dB and the LO signal suppression over 30 dBc at the LO input power of 0 dBm. Owing to a novel BST (Barium Strontium Titanate) capacitor technology, the implemented mixer IC was packaged in the small 6 pin outline with the extremely small chip size of 0.6/spl times/0.65 mm/sup 2/. The IC can eliminate the LO filter of the up-conversion system for a variety of handyphone-sets in L-band. >

Shielded electrical connector component assembly

Abstract: A shielded housing provides electrical shielding for connection components supported therein The shielded housing may form a balun for providing impedance matching between a twisted pair cable and a coaxial or twinaxial cable A shielded balun housing supports balun components including a pair of shielded connector components and an electrical circuit interconnecting the components The housing includes upper and lower housing members which are secured together in a manner which establishes conductive engagement therebetween The housing provides electromagnetic shielding between the balun and adjacent components

Coupling device connecting an unbalanced signal line to a balanced signal line

Abstract: Disclosed is a passive, highly efficient, low noise coupling device that includes a balun (14) and noise reduction circuitry uniquely configured for converting an unbalanced video signal on a 75 ohm transmission line or connector to a balanced signal on a 100 ohm transmission line or connector and vice versa. The device efficiently allows use of a 100 ohm unshielded twisted pair, such as a conventional telephone cable, for multiplex transmission of video signals or the like in the frequency range of 50 to 500 megahertz. The preferred embodiment has a circuit board with a 75 ohm unbalanced side and a 100 ohm balanced side separated by a balun having a toroid core with a very high permeability. A common mode choke (16) for noise rejection is inserted in the balanced side. The choke has a dual toroid core, one core of high permeability and one of low permeability, and has windings with a 100 ohm characteristic impedance. A common mode toroid shunt (18) on the device's balanced side provides further noise reduction. Circuit board traces connecting the components are impedance-matched to either the balanced side or the unbalanced side as appropriate.

Cable test instrument having interchangeable performance modules

Abstract: A test instrument (50) for testing a cable (52), the test instrument having a main unit (54) and an interchangeable performance module (56). The main unit of the test instrument contains signal generators for generating AC and DC test signals. The AC test signals are generated as single-ended signals and applied to a pair selection switching array (76). The pair selection switching array switches the single-ended test signals to a plurality of lines (84a-84d) that couple to the performance module. The performance module is an interchangeable module having a plurality of balancing networks (baluns) (102a-102d) that are connected to the plurality of lines. Single-ended test signals applied to the baluns are converted into balanced signals and applied to a cable being tested. The performance module may be interchanged to allow the main unit to be connected to cables having various impedances and connectors. The conversion to a balanced signal after the switching array improves the test instrument accuracy and allows the switching array to be constructed of transistors.

Novel single device balanced resistive HEMT mixers

Abstract: A family of novel single device balanced resistive HEMT mixers has been designed and characterized. The RF is fed through a 180/spl deg/ balun. The IF is extracted either by a 180/spl deg/ balun or single ended. The main advantages of this type of mixer are that no device pairing is necessary, since only one HEMT is used and that no RF and LO grounding is necessary. These advantages make the described topology particularly suitable for microstrip MIC's, MMIC's, crossbar, fin-line and quasi optical mixers. The mixers are designed for RF 17.5-20 GHz, the LO is wideband and the IF is 1-2 GHz. Measurements show a conversion loss of 6 to 8 dB and an LO to RF isolation of up to 37 dB (typically 20 dB).

Quasi-double balanced passive reflection FET mixer

Abstract: FET mixers requiring relatively low local oscillator power levels and having excellent isolation of the local oscillator signal relative to the radio and intermediate frequency signal. The mixer comprises a first and second FET transistor (Q1, Q2) having their gates and sources connected together such that the first and second FET transistors are in series; a local oscillator input circuit; a coupling network comprising a transmission line balun; a diplexer circuit; and a bias circuit. In one aspect, the transmission line balun divides the voltage of an incident traveling wave equally between the first and second transmission line components, and sums the currents of traveling waves generated by the transmission line components to generate an exitant traveling wave signal. The RF signal is completely reflected by each the FET transistors with no phase shift when they are nonconducting (OFF), and completely reflected by each of the FET transistors with a 180° phase shift when they are conducting (ON) owing to the different relative impedances. A diplexer circuit separates an intermediate frequency signal from the exitant traveling wave signal, and substantially all of said RF signal incident on the first and second FETs is reflected from the FETs during ON and OFF conduction state such that commutation of the RF signal during each half cycle of the local oscillator signal is symmetrical, and such that the RF reflected signal components in the reflected wave are substantially canceled from the exitant traveling wave to generate the intermediate-frequency (IF) signal.

Thick film balanced line structure, and microwave baluns, resonators, mixers, splitters, and filters constructed therefrom

Abstract: A thick film balanced line multilayered structure having a substrate base of nominal 0.025 or 0.030 inch thick ceramic material, a first metal layer deposited on the substrate base, a nominal 0.003 inch thick dielectric layer deposited over and around the first metal layer, and a second metal layer deposited on top of the dielectric layer in alignment with, and parallel to, the first metal layer. The structure defines a standard circuit cell suitable for use as a balun, a capacitor or an autotransformer, for use in microwave mixers, power splitters, filters, resonators and other microwave devices. The impedance of the cell is controlled by the width of the metal layers, and ranges from 5 ohms to 125 ohms, and the frequency of the cell is controlled by the length of the metal layers.

High dynamic range mixer having low conversion loss, low local oscillator input power, and high dynamic range and a method for designing the same

Abstract: A double-double-balanced mixer includes first and second radio frequency baluns and first and second local oscillator baluns formed on a dielectric substrate and connected to two diode rings. An intermediate frequency port is also connected to two diode rings. The particular dimensions of the stripline mixer are carefully selected to provide high dynamic range, strong suppression of intermodulation products, low conversion loss, and low local oscillator input power. The specific design dimensions of the mixer are selected contrary to conventional mixer design principle. For example, the local oscillator and radio frequency balun microstrips are designed to have a length which is considerably less than one-quarter wavelength of the LO and RF frequencies.

A monolithic broadband doubly balanced EHF HBT star mixer with novel microstrip baluns

Abstract: This paper describes a planar MMIC HBT Schottky diode mixer utilizing novel baluns fabricated on a 4 mil thick GaAs substrate. The balun is based on the Marchand balun structure and is implemented in a microstrip environment. The balun structure consists of 7 closely coupled microstrip lines and backside vias. Four 10/spl times/10 /spl mu/m/sup 2/ HBT Schottky diodes in a star configuration provide the mixing function. The HBT diodes have cut-off frequencies in excess of 750 GHz. The mixer achieves 8-10 dB conversion loss and very low spurious responses over a 26-40 GHz RF and LO bandwidth and DC-11 GHz IF. This IF bandwidth is broader than a previously demonstrated CPW star mixer using InGaAs HEMT technology, and easier to integrate into an assembly due to its microstrip implementation. >

Lumped parameter balun

Abstract: A balun, which does not use magnetic coupling and is easily integrated in MMICs, is formed of lumped parameter inductive and capacitive circuit elements. In one embodiment, a termination circuit is utilized to prevent reflections of common mode signals.

Broadband single- and double-balanced resistive HEMT monolithic mixers

Abstract: A double-balanced (DB) 3-18 GHz and a single-balanced (SB) 2-16 GHz resistive HEMT monolithic mixer have been successfully developed. The DB mixer consists of a AlGaAs/InGaAs HEMT quad, an active LO balun, and two passive baluns for RF and IF. At 16 dBm LO power, this mixer achieves the conversion losses of 7.5-9 dB for 4-13 GHz RF and 7.5-11 dB for 3-18 GHz RF. The SB mixer consists of a pair of AlGaAs/InGaAs HEMT's, an active LO balun, a passive IF balun and a passive RF power divider. At 16 dBm LO power, this mixer achieves the conversion losses of 8-10 dB for 4-15 GHz RF and 8-11 dB for 2-16 GHz RF. The simulated conversion losses of both mixers are very much in agreement with the measured results. Also, the DB mixer achieves a third-order input intercept (IP/sub 3/) of +19.5 to +27.5 dBm for a 7-18 GHz RF and 1 GHz IF at a LO drive of 16 dBm while the SB mixer achieves an input IP/sub 3/ of +20 to +28.5 dBm for 2 to 16 GHz RF and 1 GHz IF at a 16 dBm LO power. The bandwidth of the RF and LO frequencies are approximately 6:1 for the DB mixer and 8:1 for the SB mixer. The DB mixer of this work is believed to be the first reported DB resistive HEMT MMIC mixer covering such a broad bandwidth. >

Analysis and design of multi-octave MMIC active baluns using a distributed amplifier gate line termination technique

Abstract: The analysis and design of a multi-octave MMIC active balun is described in this paper. The technique employed uses the gate-line 'termination' of a distributed amplifier topology as a non-inverting output. Closed-form expressions for the two output signals have been derived. The MMIC prototype has achieved balun operation over 0.5 to 20 GHz with a 10/spl deg/ maximum phase error. >

Unbalanced to balanced signal line coupling device

Abstract: Disclosed is a passive, highly efficient, low noise coupling device that includes a balun and noise reduction circuitry uniquely configured for converting an unbalanced video signal on a 75 ohm transmission line or connector to a balanced signal on a 100 ohm transmission line or connector and vice versa. The device efficiently allows use of a 100 ohm unshielded twisted pair, such as a conventional telephone cable, for multiplex transmission of video signals or the like in the frequency range of 50 to 500 megahertz. The preferred embodiment has a circuit board with a 75 ohm unbalanced side and a 100 ohm balanced side separated by a balun having a toroid core with a very high permeability. A common mode choke for noise rejection is inserted in the balanced side. The choke has a dual toroid core, one core of high permeability and one of low permeability, and has windings with a 100 ohm characteristic impedance. A common mode toroid shunt on the device's balanced side provides further noise reduction. Circuit board traces connecting the components are impedance matched to either the balanced side or the unbalanced side as appropriate.

FDTD diakoptic design of a slot-loop antenna excited by a coplanar waveguide

Abstract: Acompact slot loop antenna is designed in this paper. Here a curved slotline loop, coplanar waveguide fed to slotline transition balun and short-end coplanar matching network are all analyzed piecewise by a three dimensional FDTD method working on a diakoptics basis. The symmetric feature of the circuit is explored and a new multiple excitation technique is employed to aid analysis. Measurement results show that the FDTD diakoptics design technique is accurate and offers potential for mixed geometry or high resolution problems which must be decomposed into smaller subelements which are more convenient from a computational perspective.

Direct-coupled active balanced mixer

Abstract: A low power, high-performance mixer includes a Schottky diode ring and first and second active baluns. The first active balun has an input coupled to a radio frequency (RF) signal and generates a first intermediate frequency (IF) output and a set of balanced RF outputs which are directly coupled to the Schottky diode ring. A second active balun has an input coupled to a local oscillator (LO) signal and generates a second IF output and a set of balanced LO outputs which are directly coupled to the diode ring. An IF output combiner, coupled to the first and second IF outputs, generates a combined IF output from the first and second IF outputs. The mixer can alternately be implemented using first and second distributed active baluns which are directly coupled to the diode ring.

Planar triply-balanced microstrip mixer

Abstract: A planar triply-balanced microstrip mixer for microwave and millimeter wave operation includes an RF port, and IF port and an LO port. The mixer is constructed on a single side of a two-sided substrate. The single side of the substrate supports an RF balun network connected to the RF port, an IF balun network connected to the IF port, and an LO balun network connected to the LO port; a pair of crossover diode ring quad circuits arranged in a planar back-to-back configuration; and a planar microstrip feed network connecting the RF, IF, and LO ports to the diode ring quad circuits through the RF, IF and LO balun networks.

A wideband balun from coaxial line to TEM line

Abstract: Present requirements for ultra wideband systems involve the design of antennas having bandwidths of 1 to 4 octaves. Suitable directive antennas are TEM horns but the connection between the input line to a TEM horn and the associated electronics must be designed with care. The ideal input arrangement is an end-fed connection from input coaxial line to a parallel plate line which flares into the TEM horn. This arrangement requires a balun (balance-to-unbalance transformer) and a balun design transforming directly from coaxial line to TEM line is desirable. A design approach used was to transform directly from a coaxial line to a TEM line based on a variant of the technique of Duncan and Minerva (1960) for the first half of the balun and then using a method of moments technique to determine the impedance of the rest of the structure. The length of the complete balun is lambda /4 at the lowest frequency. The disagreement between the design specification and the measurements is less than 2 ohms over the balun length in spite of the necessity to include strengthening ridges in the design.

Quasi-double balanced dual-transformer dual FET mixer, which achieves better isolation by using a first and second diplexer, and a transmission line RF balun

Abstract: A double balanced dual-quad transformer dual field effect transistor (FET) mixer is disclosed using a first and second (FET) which have their gates electrically connected together, such that the first and second FET are connected in series The mixer achieves improved isolation by using a first and second diplexer, and an RF and IF coupling network which comprises a flux-coupled IF transformer and a transmission line RF balun

Generation of balanced subnanosecond pulses using step-recovery diodes

Abstract: A method for generating balanced subnanosecond pulses is described By using pulsed bias techniques to excite a step-recovery diode via a conventional ferrite balun transformer, a balanced step waveform can be taken directly from the diode itself, eliminating the requirement for a broadband output balun transformer The resulting pulses are suitable for applications in broadband antenna excitation, time-domain reflectometry and high-speed sampling bridges

Hybrid antenna sources for radiating high-power impulsive fields

Abstract: The transmission of impulsive signals through baluns and feed lines, between high-power, fast-risetime pulse generators and impulse-radiating antennas, leads to degraded system performance and increased pulse risetime due to transit-time dispersion, skin and dielectric losses, and electrical breakdown effects. These loss mechanisms are greatly reduced in system designs that eliminate feed lines and baluns by combining the antenna and generator in a single hybrid device that is compact, simple, and robust. This paper describes generators in which the antenna itself is pulse charged to hundreds of kV and subsequently shorted at the feed point by an oil spark switch. These Hertzian generators maintain conical symmetry to within a few millimeters of the feed-point switch, thus providing conditions for launching near-ideal spherical TEM step waves for driving impulse-radiating, focused-aperture antennas. Careful attention to symmetry, optical principles, and precise methods of measurement has yielded subnanosecond pulse risetimes that are more than ten times faster than predictions from spark- switch scaling laws.

A reduced size planar balun structure for wireless microwave and RF applications

Abstract: An extremely important component in the realization of certain RF and microwave system topologies is the high frequency balun network. In addition to its application in radiating structures, it has broad utility in numerous wireless communication system topologies. This paper describes a small and compact coupled microstrip line design for use primarily in the exploding portable wireless market. The main advantage of the design to be discussed is that its size is considerably smaller than traditional planar circuit realizations. Size reduction is achieved by utilizing the property of effective length enhancement of a transmission line by employing additive capactive effects. The design technique is illustrated by presentation of computed and measured data on a /spl sim/0.9 GHz realization developed for wireless applications.

A high gain YBCO antenna array with integrated feed and balun

Abstract: A supergain antenna array of closely spaced printed dipoles made of thick film YBCO was designed and experimentally tested. An optimization of the directive gain with respect to interelement spacing, dipole length, and other circuit parameters, subject to constraints in array size, was performed by combining the spectral domain method of moments and transmission line theory. The design procedure accounts far losses associated with the strip material, both at the feed and the radiating dipoles, and power dissipation in the substrate. A practical design of a sixteen element array is demonstrated, with an integrated feeding network and a balun, also made of high-T/sub c/ superconductors (HTS). Performance is compared against simulated data. The superconducting array has gain significantly higher than that of a similar supercooled silver array albeit at the expense of transmission bandwidth. It is shown that supergain is practically achievable by miniature, printed HTS dipole arrays. >

High-efficiency power amplifier

Abstract: PURPOSE:To realize a high-efficiency power amplifier of class 'F' operation capable of adjusting the balun, which short-circuits even-order waves, and an odd-order wave adjusting circuit, which opens odd-order waves, independently of each other in the output end face of a semiconductor element. CONSTITUTION:Unit amplifiers each of which consists of an input-side fundamental wave matching circuit 103, a semiconductor element 104, and output-side fundamental wave and harmonic matching circuits 105 and 106 are connected in parallel with a phase inverting circuit 102 on the input side and with a balun 108 on the output side. The electric length from the input end of a power synthesizing circuit on the output side to the output end of each semiconductor element is set to oddfold 1/8 wavelength of the fundamental wave, and it is set to even-fold 1/8 wavelength in the case of a focible balun, thereby short-circuiting the even-order wave impedance in the output end of the semiconductor element. The odd-order wave adjusting circuit is connected between the two points, which have the same electric length from semiconductor element output ends of respective unit amplifiers and are in the rear parts of output-side fundamental wave and harmonic matching circuits, to open the odd-order wave impedance in the output ends of semiconductor elements, thus satisfying the condition of class 'F' operation.

Universal audio/video signal converter

Abstract: In low power audio and video applications, an audio/video signal converter converts balanced and unbalanced signals using a first converter which converts a balanced signal to an unbalanced signal and a second converter which converts an unbalanced signal to a balanced signal The first and second converters may be selected (either separately or in any combination) based on any desired signal conversion The input impedances, output impedances, and the gains, of each of the first and second converters, may be adjusted either manually or automatically, and either independently or jointly, for proper loading and termination of signals

A Hi h Gain YBCO Antenna Array wit a Integrated Feed and Balun

Abstract: A supergain antenna array of closely spaced printed dipoles made of thick film YBCO was designed and experimentally tested. An optimization of the directive gain with respect to interelement spacing, dipole length, and other circuit parameters, subject to constraints in array size, was performed by combining the spectral domain method of moments and transmission line theory. The design procedure accounts far losses associated with the strip material, both at the feed and the radiating dipoles, and power dissipation in the substrate. A practical design of a sixteen element array is demonstrated, with an integrated feeding network and a balun, also made of high-T/sub c/ superconductors (HTS). Performance is compared against simulated data. The superconducting array has gain significantly higher than that of a similar supercooled silver array albeit at the expense of transmission bandwidth. It is shown that supergain is practically achievable by miniature, printed HTS dipole arrays.<>

Smithdom improved multiband antenna and method

Abstract: A broadband off-center fed dipole antenna capable of resonating at multiple frequencies with a near integer relationship between fundamental and harmonic frequencies and with standing wave ratio of less than or equal to 1.5:1 at desired frequencies without the need of an antenna tuning device. One preferred embodiment of the antenna comprises a first radiating section having an inner line electrically coupled to a balun transformer and a trap and an outer line electrically connected to the trap and an insulator. A second radiating section is connected to the balun transformer and has another insulator secured to its other end.