Showing papers on "Balun published in 1994"

Review of printed Marchand and double Y baluns: characteristics and application

Abstract: A review of printed baluns is presented. This is divided into two main groups; Marchand baluns (band pass networks) and double Y baluns (all pass networks). For each of these groups of baluns, three different realizations are given: microstrip-slot line, CPW-slot line and CPW/sub FGP/-CPS and their theoretical and experimental characteristics are compared. Simple expressions for the design of Marchand baluns with Chebyshev response, which replace the complicated synthesis proposed by Cloete are derived. Superior broadbandwidth features of double Y baluns are demonstrated in the design of two uniplanar double balanced mixers. Both the double Y mixer and the CPW/sub FGP/-CPS mixer have a frequency bandwidth 1:6, whilst maintaining other performance similar to that achieved with classical double balanced mixers. >

New uniplanar coplanar waveguide hybrid-ring couplers and magic-T's

Abstract: The uniplanar coplanar waveguide (CPW) and slotline on a dielectric substrate have many applications to MIC and MMIC designs. A new reverse-phase CPW hybrid-ring coupler and a uniplanar CPW magic-T were developed. Experimental results showed that the hybrid-ring coupler has a 60% bandwidth centered at 3 GHz and the magic-T has a bandwidth of one octave from 2 to 4 GHz with 0.4 dB amplitude imbalance and 3.5/spl deg/ phase imbalance. Also, this paper presents theoretical analyses of CPW-slotline transitions using the transmission line models. Accurate modeling of nonuniform CPW and slotline radial stubs was developed using tandem connected uniform lines. Measured results of various CPW-slotline transitions agree very well with calculation. Design curves of the transitions are given for practical applications. To fully use the advantages of uniplanar structures, a 180/spl deg/ reverse-phase CPW-slotline back-to-back balun and a tee junction are described. Both circuits provide good amplitude and phase characteristic over a broad bandwidth due to the phase change of the circuits being independent of frequency. >

Balun apparatus including impedance transformer having transformation length

Abstract: An electrical connection between a balanced circuit, such as a radio receiver and an unbalanced circuit, such as an antenna requires a balun. In a small electronic device such as a radiotelephone, a traditional balun is impractical because of the physical constraints. The balun function is performed by using a transmission line of minimum transverse dimensions and a predetermined length between the receiver and the antenna.

Microstrip DC-to-GHZ field stacking balun

Abstract: A wideband (DC to GHz) PC-board Balun that is disclosed. The balun mainta low insertion loss and good balance for ultra wide band (UWB) applications such as impulse radar. The balun structure is formed by microstrip transmission lines on a dielectric substrate, having at least one inverting and one non-inverting transmission lines. The transmission lines are connected to form balanced transmission lines stacked about a ground plane. N transmission lines can be connected to form a N 2 :1 impedance ratio balun. Ferrite cores placed about the transmission lines and resistor-capacitor circuits improve the low frequency operation of the balun.

Compact low-loss microwave balun

Abstract: A microwave balun is constructed by combining a four-transmission-line branch-line coupler with a single-transmission-line delay element This construction results in a simplified, compact arrangement for combining first and second signals applied to respective first and second ports, phase shifted by 180°, and providing the combined signal at a third port The balun is a reciprocal device and may be operated in reverse with a signal applied to the third port to obtain outputs at the first and second ports

Antenna for an electronic apparatus

Abstract: An antenna (i06) for an electronic apparatus is located in a flip element (104) of the apparatus housing. A transformer (108), having a winding (201) in the flip element (104) and a winding (301) in the housing couples electromagnetic energy across the hinge while impedance matching and performing a balun function.

Common mode current cancellation in twisted pairs

Abstract: A method for connecting together two twisted pair lines in a LAN so as to avoid common mode current The invention recognizes that the impedance to ground is different for each wire in the twisted pair line Moreover, this impedance is different from spool-to-spool for lines having the same purported impedance A balun is placed at the connection between the lines

Computer-aided analysis and design of a planar multilayer Marchand balun

Abstract: Analytical expressions for the scattering (S) parameters for a planar multilayer Marchand balun, constructed of broadside-coupled microstriplines, are derived for the first time, based on the coupled-line quasi-TEM normal mode parameters. New design equations and a new design procedure for the balun based on the derived S-parameters and a circuit synthesis technique are presented. Calculated results for a GaAs microwave monolithic integrated circuit balun designed by this procedure are compared to a general full-wave planar analysis, and good performance and agreement are obtained. >

Flat cable to flat parallel wire cable

Abstract: A LAN which uses flat telephone cable having at least four conductors. The inner conductors are joined together and the outer conductors are joined together at each node thereby making reversals of the inner and outer conductors, which may occur at connectors, impossible. Each node uses two baluns to provide an unbalanced zone between the baluns for connecting to the DTE.

A compact wideband balanced mixer

Abstract: A compact wideband balun using a common-gate/common-source approach has been developed. Using this active balun on the LO port, a passive interdigital microstrip balun on the RF port, and a passive lumped element L-C balun on the IF port, a wideband balanced mixer was designed, fabricated and tested. This paper describes the mixer circuit design based on a new passive FET model. Test results of the active balun and the mixer including conversion loss, noise figure, and third order intercept point are presented for RF frequencies from 4 to 18 GHz. >

EMI filter and method

Abstract: An improved EMI filter design is provided for an inverter operated dynamoelectric machine. A lossy balun wound choke is connected between a power supply in the form of a bridge rectifier and the inverter. The choke acts as a source resistance. Using the choke as the source resistance, an equiripple approximation to linear phase filter is derived. The filter is placed on the input side of the bridge rectifier. A method of designing an EMI filter for use in conjunction with an inverter operated dynamoelectric machine.

End-on transmission line-to-waveguide transition

Abstract: A transmission line-to-waveguide transition that includes a microstrip impedance transformer for matching the impedance of an input transmission line to that of a flared slotline is disclosed. The slotline's width is sufficiently small such that when the transition is inserted into a waveguide the slotline is spaced inward from the waveguide's inner walls. A balun bi-directionally couples the unbalanced signal on the microstrip to a balanced signal on the slotline. The signal propagates along the slotline and is capacitively coupled to the waveguide. A trimmable tuning stub is used to adjust the resonant frequency of a parasitic cavity formed between the transition and the waveguide to increase the transition's effective bandwidth. A tapered dielectric insert is positioned inside the waveguide to decrease its size and to improve the coupling efficiency of the transition.

Modeling and design of novel passive MMIC components with three and more conductor levels

Abstract: Novel passive MMIC components with 3, 4 or more conductor levels have been investigated. They are described by a simulation approach which is a generalization and improvement of previous approaches for 1 and 2 metal levels. Simulated S-parameters agree well with measurements for spiral inductors using 4 conductor levels. The design of MMIC broadband transformers with small space consumption and coverage of 2-3 octaves (5 to 22 GHz and 0.6 to 4.2 GHz, respectively) is discussed. Also, a compact broadband balun for 10-40 GHz operation is given as an example. >

Radio frequency antenna

Abstract: A quadrifiliar radio frequency antenna intended primarily for the reception of circularly polarised transmissions has the helical antenna elements (10A - 10D) deposited upon a dielectric material of high dielectric constant and of cylindrical form (13). Within the cylinder is contained the means whereby the signals received by the said elements are transformed to a form more suitable for further processing eg. a split tube balun (see Fig. 2 not shown). This is achieved by depositing conductors upon a dielectric material of high dielectric constant and of cylindrical form (22), co-axial with (13). Around the cylinder (13) if a further cylinder (19) which provides a means of varying the operating frequency. The interconnection of the parts into a rigid single assembly is to be achieved by a single soldering operation. The results in a smaller than could be achieved using prior art. The antenna is especially useful for GPS reception.

Radiofrequency ground heating system for soil remediation

Abstract: An in-situ method of extracting contaminants from a soil volume comprises applying a radiofrequency (RF) excitation signal to heat the soil with an array of electrodes. The electrodes are inserted into the contaminated volume or inserted into a matrix of holes drilled into the volume. A first row of electrodes is electrically coupled to a shield of a coaxial cable, with a second row electrically coupled to the central conductor of the coaxial cable. RF energy is applied to pairs of electrode rows through the coaxial cable and a matching network is installed in front of the electrode-row pair to maximize power flow into the electrode-row pair. This results in very evenly distributed voltages which results in even heating. A balanced-to-unbalanced transformer (balun) is installed at the input to the matching network to prevent the deposition of RF energy outside the target volume and creation of voltages that could be hazardous to personnel. The electrodes are perforated and connected to collection tubes which collect volatilized contaminant vapors and pass the vapors to a vapor treatment unit for neutralization.

A multiband antenna system

Abstract: There is described a multiband antenna system for operating at L-band, S-band and UHF-band comprising L-band antenna elements (1) and S-band antenna elements (2) provided in the form of quadrifilar helices spaced from each other on the surface of a hollow cylindrical insulator (4); UHF band antenna elements (3) provided in the form of a cage dipole on the surface of the said hollow cylindrical insulator (4); the L-band antenna input being connected to a first connector (5) through an L-band feed network card (8); the S-band antenna input being connected to a second connector (6) through an S-band feed network card (9) and the UHF-band antenna input being connected to a third connector (7) through a split sheath balun (10) provided along the axis of the said hollow cylindrical insulator (4).

Microwave integrated circuits

Abstract: 1 Introduction.- References.- 2 Analysis of passive circuit elements.- 2.1 Transmission Lines for Microwave Integrated Circuits.- 2.1.1 Basic characteristics of homogeneous transmission lines.- 2.1.2 Microstrip lines.- 2.1.3 Suspended and inverted microstrip line.- 2.1.4 Coplanar line.- 2.1.5 Slot-line.- 2.1.6 Fin-line.- 2.1.7 Coupled lines.- 2.1.8 Methods of homogeneous line analysis.- 2.2 Discontinuities by M. Pavel.- 2.2.1 Characteristics of discontinuities and their use in MIC.- 2.2.2 Methods of discontinuity analysis.- 2.2.3 Microstrip discontinuities.- 2.2.4 Discontinuities in other transmission lines for MIC.- 2.3 Lumped elements.- 2.3.1 Use of lumped elements.- 2.3.2 Capacitive elements.- 2.3.3 Inductive elements.- 2.3.4 Resistive elements.- References.- 3 Modelling of active semiconductor circuit elements.- 3.1 Schottky-barrier diodes.- 3.2 Varactor diodes.- 3.3 p-i-n diodes.- 3.4 Bipolar transistors.- 3.5 MESFETs.- 3.6 HEMTs.- References.- 4 Basic circuits.- 4.1 Methods of the MIC synthesis by I. Kneppo and J. Fabian.- 4.1.1 The matrix representation.- 4.1.2 Network matrix decomposition.- 4.1.3 Synthesis of n-port on the base of elementary two-ports.- 4.1.4 Nonlinear MICs.- 4.2 Basic linear circuits by P. Bezousek, F. Hrni?ko and M. Pavel.- 4.2.1 Non-reflecting termination.- 4.2.2 Resonators.- 4.2.3 Matching transformers.- 4.2.4 Low-pass filter.- 4.2.5 RF chokes.- 4.2.6 Band-pass filters.- 4.2.7 Attenuators.- 4.2.8 Power dividers.- 4.2.9 Directional coupling and hybrid elements.- 4.2.10 Differential phase shifter.- 4.2.11 Baluns and magic-tee.- 4.3 Basic active non-linear circuits by P. Bezousek, F. Hrni?ko and M. Pavel.- 4.3.1 Detectors.- 4.3.2 Mixers.- 4.3.3 Oscillators.- 4.3.4 Amplifiers.- 4.3.4.1 Low-noise amplifiers.- 4.3.4.2 Power amplifiers.- References.- 5 Measuring and testing.- 5.1 Incorporation of the MIC measured into the measuring system: Microwave test fixtures and probes.- 5.2 Measurement techniques.- 5.2.1 S-parameter measurement.- 5.2.2 Noise measurement.- References.

A planar broadband balanced doubler using a novel balun design

Abstract: We report on the design and measurement of a broadband MIC balanced varactor frequency doubler. The design incorporates a novel balun to achieve a grounded CPW-to-slotline transition. The balanced structure offers inherent isolation in the output port from all odd harmonics including the fundamental frequency. Measurements show a port-to-port conversion loss between 8 and 10 dB over an output frequency range of 6-10 GHz. The design can be easily scaled to millimeter-wave frequencies using a monolithic approach. >

Design Considerations for Ultra-Wideband, High-Voltage Baluns

Abstract: : We consider how to build a balun for fast-risetime pulses at high voltage. We are concerned about signals with risetimes on the order of 100-200 ps with high peak voltages and peak powers. We propose the simplest method is a coaxial unzipper. We consider (1) the dielectric strength and maximum coaxial radius allowable while still maintaining the risetime, and (2) methods to reduce the coupling to the common mode. Finally, we calculate the peak electric field and characteristic impedance of the coaxial unzipper at various points along its length using a two-dimensional finite element code. The results of this design will be used to build an ultrawideband antenna system.

A broadband planar image reject mixer

Abstract: A 6-18 GHz Image Reject Mixer (IRM) is presented that is smaller and less expensive than the present suspended stripline technology products. The cost was reduced by designing novel building blocks that could all coexist on a single microstrip substrate. The novel components are quadrature couplers at IF and RF frequencies and a microstrip balun. Design methodology is presented along with measurements. Finally, the whole IRM is put together and characterized state-of-the-art performance is achieved and presented. >

Directional coupler tap and system employing same

Abstract: A lumped element directional coupler tap is disclosed especially adapted for a system providing bi-directional communications. The directional coupler tap includes three resistors and a balun. A radio frequency signal may be tapped off of a main transmission line to feed a plurality of branch lines as in a cable television system. The coupler exhibits a high degree of isolation between tap and load ports, and good performance over an usually broad frequency range.

A measurement of balanced transmission lines using S-parameters

Abstract: A new method for measuring both balanced and unbalanced parameters of a twisted pair cable up to 500 MHz is presented. The parameters are derived from the unbalanced data measured by a conventional network analyzer with an S-parameter test set without using balanced-to-unbalanced conversion transformers (baluns). The common mode rejection ratio (CMRR) of the measurement system is -70 dB constant over the frequency range from 10 kHz to 500 MHz. The resultant data matched within 0.5 dB for insertion loss and 3% for the characteristic impedance with those measured by a conventional method using balun. The data of the near end crosstalk also matched well at the frequency range higher than 1 MHz. >

Circuit and method for balun compensation

Abstract: A novel circuit and method for providing amplitude and phase compensation for a balun in order to provide first and second voltage signals that are balanced has been provided. The compensation is achieved by adding an amplitude and phase compensation circuit such as a transmission line (14) or inductive (20) and capacitive (22) lumped elements in series with one of the ports of the balun on the balanced side. The amplitude and phase compensation circuit includes a characteristic impedance parameter (Zo) and an electrical length parameter (Eo) that are optimized such that the amplitude difference between first and second voltage signals is minimized, while the magnitude of the phase difference between first and second voltage signals is maximized.

Broadband microwave mixer mounted on suspended line baluns

Abstract: The performance of a microwave balanced mixer which is mounted on the suspended microstrip baluns is investigated. The mixer is in the conventional double-balanced ring form and the two ports (RF and IF) are terminated by the same real impedance (50 ohms). The pump power requirements for to provide matching at either ports is investigated and the conversion losses are calculated. A new type of balun is proposed for RF port termination which is consist of a normal microstrip and a phase inverting suspended microstrip line. It is shown that this balun theoretically has infinite bandwidth when the odd-order characteristic impedance of the suspended line Y/sub oo/=2Y/sub 0/. The mid frequency of operation is selected as 10 GHz and the bandwidth of about 2 octave (3-12 GHz) with less than 8 dB loss (6 dB measured at 9 GHz). >

A planar broadband MIC balanced varactor doubler using a novel grounded-CPW to slotline transition

Abstract: We report on the design and measurement of a broadband MIC balanced varactor frequency doubler. The design can be easily scaled to millimeter-wave frequencies using a monolithic approach. The design incorporates a novel balun to achieve a grounded-CPW to slotline transition. The balanced structure offers inherent isolation in the output port from all odd harmonics including the fundamental frequency. Measurements show a port-to-port conversion loss between 8 and 10 dB over an output frequency range of 6-10 GHz. >

A Novel MMIC Balanced FET Mixer with Superior Performance

Abstract: The design and performance of a new type of monolithic balanced FET mixer is described in this paper. The mixer which measures 3mm × 2.4mm, exhibits at the centre frequency a conversion gain of 2dB (using lOdBm LO power), over 40dB of RF to IF isolation, over 55dB of LO to IF isolation, over 25dB of RF to LO isolation and a ldB compression gain at ldBm of RF input power. The technique employed in the design is to use a common gate/common source FET pair in a conguation which conveniently performs both mixing and balun functions, thus eliminating the need for large and complex balancing circuitry. Active signal combining techniques are also employed in order to maintain a completely active balanced mixer which is capable of providing conversion gain and compactness of size. The excellent measured results have indeed verified the design and so the mixer is suitable for applications in a wide range of monolithic microwave systems and subsystems.

Magnetic resonance video device and probe for magnetic resonance video device

Abstract: PURPOSE:To prevent the generation of a ground loop and to obtain good images by providing at least a part of the earth conductors of a means for connecting the signal reception signals by signal receiving coils for receiving magnetic resonance signals to preamplifiers for amplifying the signal reception signals with high-impedance sections CONSTITUTION:This magnetic resonance video device impresses magnetic field gradients changing linearly in directions X to Z from gradient magnetic field forming coils to a examinee, impresses high-frequency magnetic fields from the coils for signal reception and receives the magnetic resonance signals from the examinee by surface coils 17a, 17b which are the coils for signal reception There is a tendency to the generation of the ground loop by the floating capacitances, etc, between the surface coils 17a, 17b and the earth conductors and, therefore, baluns 21a, 21b of a bazooka type are formed on coaxial cables connecting the coils 17a, 17 and the preamplifiers 18, 18b in such a case As a result, the electrical coupling of the signal transmission coils and the ground loop is averted and the uniform irradiation with the high-frequency magnetic fields is possible

A CAD procedure for the double-layer broadside-coupled Marchand balun

Abstract: New design equations and a new computer-aided design (CAD) procedure for the double-layer Marchand balun, constructed of broadside-coupled microstrip lines, are presented, based on the derived scattering parameters and a circuit synthesis technique. The developed procedure can determine accurately and quickly both initial electrical and physical parameters of the balun for achieving a desired performance, as well as provide an accurate and simple analysis. Calculated results for a GaAs MMIC balun designed by this procedure are compared to a general full-wave analysis, and good performance and agreement are obtained. >

Balanced phase modulator used in microwave band

Abstract: A phase modulator for microwave band having a desirable modulation characteristic by maintaining the impedance thereof constant, comprising two PIN diodes (2) and (3) connected to a merchant balun (1) and a bias circuit (18) which supplies bias voltages to the PIN diodes (2) and (3) such that the sum of the bias voltages applied to the diodes (2)and (3) to be constant. The bias voltages are selected so as to have the input and output impedances to be in the most stable state when a modulation signal is equal to zero.

Modeling baluns with the method of moments

Abstract: When using the method of moments (MoM) to model large arrays with large numbers of balanced feeds, the feed baluns can always be incorporated into the analysis by combining the multiport admittance matrix for the array with the admittance matrices of the baluns. This technique is straightforward but requires that the MoM equations be solved for a large number of right-hand sides. The paper shows how the effects of perfect baluns can be incorporated directly into the MoM equations, requiring only one right-hand side. This technique yields the exact results with a significant savings in computing resources. >