Showing papers on "Balun published in 2001"

Analysis and design of impedance-transforming planar Marchand baluns

Abstract: A technique for designing impedance-transforming baluns is presented in this paper. It is based on the Marchand balun with two identical coupled lines. By varying the coupling factor of the coupled sections, a wide range of impedance transforming ratios can be achieved. In addition, a resistive network added between the balun outputs is proposed to achieve balun output matching and isolation. Microstrip baluns, matched at all ports, for transforming from a 50-/spl Omega/ source impedance to 40-/spl Omega/ as well as 160-/spl Omega/ load terminations are realized to demonstrate the technique.

Reconfigurable diplexer for communications applications

Abstract: The present invention provides a reconfigurable diplexer which is well suited for use with mulitple element antenna arrays. The diplexer includes a common, slot-line transmission line adapted to carry electromagnetic signals; a pair a separate slot-line transmission lines coupled to the common transmission line; each separate slot-line transmission line having an individual filter coupled thereto, wherein each filter is adapted to selectively give its respective separate slot-line transmission line a characteristic impedance dependent upon predetermined frequencies of the electromagnetic signals; and a separate slot-line balun associated with each separate slot-line transmission line and adapted for coupling signals to and/or from its respective separate slot-line transmission line. The diplexer may be configured to operate in several different bands such as the INTELSAT frequencies (7.2-8.4 GHz) or DSCS frequencies (11.7-14.5 GHz).

Slot spiral antenna

Abstract: When compared to printed cavity-backed spirals, slot spiral antennas offer the possibility of designs that are conformal and very thin. We discuss the physical characteristics of a cavity-backed slot spiral, as well as the associated infinite balun and termination designs. Simulations of the proposed cavity-backed spiral are presented and used to optimize the antenna's various parameters. Comparisons of measurements and calculations are also given, to validate the gain and axial-ratio computations. Several options for miniaturizing this design, using capacitive and inductive loadings, are also presented.

Printed circuit doubly balanced mixer for upconverter

Abstract: A doubly balanced upconverter mixer includes a local oscillator balun circuit comprising juxtaposed foil elements on opposite sides of an insulated substrate with electrical interconnections between the foil elements. An IF balun circuit also comprises series tuned and parallel tuned foil elements on opposite sides of the substrate in juxtaposition to each other. A diode switching network interconnects the baluns. A local oscillator signal is connected to the foil elements of the local oscillator balun circuit, an RF signal is coupled to one foil element of the IF balun circuit and an IF signal is taken from the other foil element of the IF balun circuit. Another embodiment incorporates MESFET type switches, the gates of which are supplied directly with a symmetrical local oscillator signal. This arrangement eliminates the need for the local oscillator balun.

Highly integrated multi-layer circuit module having ceramic substrates with embedded passive devices

Abstract: A plurality of ceramic substrates are used to manufacture and integrate a highly integrated multi-layer circuit module. Integrated circuit devices are mounted on one or both surfaces of the circuit module whose multi-layer structure is divided into three types of integration regions including inter-connection integration regions, basic passive device integration regions and high frequency passive device integration regions. Connection layers are formed in the inter-connection integration regions for connecting integrated circuits. Basic passive device integration regions include capacitor, resistor and inductor layers. Filters, couplers and baluns are fabricated in the high frequency passive device integration regions. Shielding ground planes are provided for the isolation of devices to prevent electromagnetic interference. Standard input and output contacts are formed on the bottom surface so that the circuit module can be used as a modularized device.

Antenna arrays in the SIGMA-eye applicator: interactions and transforming networks.

Abstract: Objectives: In multiantenna applicators such as the SIGMA-60 or SIGMA-Eye, which consist of 4 or 12 pairs of antennas shunt to 4 or 12 amplifiers (“antenna couplets”), phases and amplitudes in the feed points of these antennas under certain conditions can significantly differ from the values selected at the multichannel amplifier (forward parameters), mainly due to coupling. In the SIGMA-Eye, this interaction is particularly affected by the transforming networks between the generators and the feed points, thus hampering the control of the feed point parameters. In this work, we perform measurements at existing applicators, present a formalism to describe the facts numerically, and investigate modifications of the transforming networks to improve the performance. Methods and Materials: We prepared an experimental setup for the SIGMA-Eye applicator that is fed by forward waves of a 12-channel amplifier system. In this setup, we made the water bolus, the interior of the tissue-equivalent phantom, and the entire transforming network accessible for measuring probes. Then, we constructed various alternative transforming networks such as Pawsey loops, LC matching networks, and power dividers and compared them with the original matching network of the SIGMA-Eye applicator. In particular, we utilized a high-resistive probe to determine the disturbances and influences caused by some channels with respect to some selected feed points of the SIGMA-Eye dipoles. Results: In the original SIGMA-Eye applicator, the influences of coupling channels on the phases and voltages in the feed point of a particular antenna are largest for adjacent longitudinal channels. Here, the ±10° phase shift and ±30% voltage change were observed if the reference channel (i.e., the disturbed channel) and disturbing channel are equally powered. The changes eminently increased to −30° to +100° phase shift and −80% to +50% voltage change if the reference channel is fed with much lower power (four to eight-fold) than the disturbing channel. The disturbance from distant channels is less but still significant, reaching shifts of −10° to +50° and −50% to +20%, respectively. Using Pawsey loops instead of the original ferrite rings in the SIGMA-Eye network, the efficacy of the baluns was improved by a more than a factor of 4. Using an LC matching network, dependencies on frequency and external arrangements can be reduced significantly. Applying a power divider circuit, the coupling between antennas combined to one channel is considerably diminished (down to <−25 dB). Conclusion: Coupling between resonators (pairs of antennas including the matching network) reduces the control of the SIGMA-Eye applicator, i.e., it causes deviations between the selection of forward parameters at the amplifier and the total actual parameters in the feed points of the antennas. Modified transformation networks can improve the control, in particular by reducing sheath currents and asymmetries. There is a linear but variable relationship between selected (amplifiers) and actually given (feed points) parameters. This linear mapping (described by a matrix) and its characteristics need further investigation.

MMIC airbridge balun transformer

Abstract: A balun transformer and inductor are proposed having geometries that provide several windings of conductors in small areas. In one embodiment, the windings of the balun transformer and inductor have octagonal shapes with a lower and upper layer of wound conductors. The upper layer lies on supporting posts that stand on pedestals. The lower layer of conductors shadow the upper layer while curving to avoid the pedestals.

A subharmonic self-oscillating mixer with integrated antenna for 60-GHz wireless applications

Abstract: A balanced integrated-antenna self-oscillating mixer at 60 GHz is presented in this paper. The modal radiation characteristics of a dual-feed planar quasi-Yagi antenna are used to achieve RF-local oscillator (RF-LO) isolation between closely spaced frequencies. The balanced mixer is symmetric, inherently broad band, and does not need an RF balun. Pseudomorphic high electron-mobility transistors are used in a 30-GHz push-pull circuit to generate the second harmonic and a 30-GHz dielectric resonator was used to stabilize the fundamental oscillation frequency. This allows the possibility of building a balanced low-cost self-contained antenna integrated receiver with low LO leakage for short-range narrow-band communication. Phase locking can be done with half of the RF frequency. The circuit exhibits a conversion loss less than 15 dB from 60 to 61.5 GHz, radiation leakage of -26 dBm at 60 GHz, and IF phase noise of -95 dBc/Hz at 100-kHz offset.

A multilayer balun transformer structure

Abstract: The present invention relates to a multilayer, balanced-unbalanced signal transformer ( 20 ) comprising a first coil and a second coil providing at least one balanced signal port at one side of the balun transformer and an unbalanced signal port at another side of the balun transformer. The (at least one) balanced signal port is provided by a first balanced signal terminal ( 23 b ) and a second balanced signal terminal ( 24 b ) formed by the ends of the first coil. The unbalanced (single-ended) signal port is provided by a first unbalanced signal terminal ( 21 u ) and a second unbalanced signal terminal ( 22 u ). It comprises a discrete component formed on a low resistivity, e.g. semiconductor substrate layer, and the first and second coils are formed in, or constitute, a first and a second metal layer such that at least a portion of one of the coils is disposed in a metal layer, or constitute a portion of a metal layer, above the metal layer in which at least a portion of the other coil is disposed, or which is constituted, at least partly, by a portion of the other coil, wherein between said first and second metal layer and between said second metal layer and the substrate layer, first and second dielectric layers are disposed. Each of said first and second coils comprises three or less winding turns.

A design of the ceramic chip balun using the multilayer configuration

Abstract: This paper presents the design method and performance characteristics of a chip-type balun using a multilayer structure. The design method for a chip-type balun is based on the lumped-element equivalent circuit of quarter-wave transformer. The proposed design method and equivalent circuit can make it easy to design the ceramic multilayer chip-type balun. The size 2012 and 3216 chip-type baluns were designed and fabricated using the proposed design method and the equivalent-circuit model of a quarter-wave transformer. Fabrications and measurements of designed chip-type baluns show smaller size than conventional chip-type baluns and good agreement with simulated results.

Chip-type LTCC-MLC baluns using the stepped impedance method

Abstract: A chip-type low-temperature co-fired ceramic (LTCC) multilayer ceramic (MLC) balun is presented in this paper. This balun is designed using the stepped impedance method. It uses a multilayer structure, meander lines, and multisection coupled lines. The use of multisection couple lines that have various characteristic impedance ratios can shrink the length of a quarter-wavelength coupled-transmission line and makes it very easy to match various impedances of balanced output. The proposed chip-type balun operates over a bandwidth of 2.25-2.65 GHz. The in-band phase and amplitude balances are excellent because of the symmetric structure and transmission-line trimming section. Measured results of the chip-type LTCC-MLC balun match well with the computer simulation.

Chip-Type LTCC-MLC Baluns Using the Stepped

Abstract: A chip-type low-temperature co-fired ceramic (LTCC) multilayer ceramic (MLC) balun is presented in this paper. This balun is designed using the stepped impedance method. It uses a multilayer structure, meander lines, and multisection coupled lines. The use of multisection couple lines that have various characteristic impedance ratios can shrink the length of a quarter-wavelength coupled-transmission line and makes it very easy to match various impedances of balanced output. The proposed chip-type balun operates over a bandwidth of 2.25-2.65 GHz. The in-band phase and amplitude balances are excellent because of the symmetric structure and transmission-line trimming section. Measured results of the chip-type LTCC-MLC balun match well with the computer simulation. Index Terms—Balun, chip-type component, LTCC, MLC, mul- tisection coupled lines, stepped impedance method.

Methods for measuring rf radiation properties of small antennas

Abstract: In this work significant improvements for measurements of the radio-frequency (RF) radiation properties of small antennas have been proposed and investigated. The main focus is on electrically small antennas as used in mobile communications systems. The methods proposed and evaluated in this thesis allow the minimisation of the dimensions of measurement chambers, and the methods also allow pattern measurements with a minimised error from the RF feed cable and thus lower measurement uncertainty. The first two parts of the work relate to measurements performed in especially small chambers. The aim is to provide an alternative measurement environment to large, fully anechoic chambers in the special case of small antenna calibrations. The use of small chambers such as GTEM cells and small anechoic chambers is proposed. Both options have been constructed and investigated by both simulations and measurements. The results show that a GTEM cell allows the reliable measurement of the radiation pattern and 3-dB bandwidth of small antennas with a low directivity and a dynamic range of less than 20 dB. A small anechoic chamber with the largest dimension of 2.5 m was built during the work for this thesis. The results obtained when measuring the 3-D radiation pattern, efficiency and the gain of a small handset antenna in that small anechoic chamber show further that far-field measurements in such a small anechoic chamber does not result in greater measurement uncertainty than results obtained in conventional large anechoic chambers. Finally, the influence of the RF feed cables on the radiation characteristics of a small antenna under test has been reduced by a novel method. This method is based on a multi-frequency balun that efficiently suppresses the propagation of leakage and parasitic currents on the shielding of the RF feed cable. The effect of the balun has been thoroughly investigated by means of computer simulations and measurements with a prototype. Both the far field and the near field have been analysed to yield a comprehensive set of figures of merit, showing that the presented balun decreases the measurement uncertainty much better than other commonly used measures against cable effects, such as ferrite beads. The balun cannot only be used in radiation-pattern measurements in large or small anechoic chambers, but also in radio-channel measurements, in near-field scans and in Standard Absorption Rate (SAR) measurements.

On-chip integrated mixer with balun circuit and method of making the same

Abstract: A radio frequency (RF) mixing device wherein RF core circuit elements requiring signal splitting are provided with one or more signal splitting element(s) (“balun(s)”) integrated on-chip with the core RF circuit elements. The RF mixing device comprises one or more RF circuit element(s) integrated on a common substrate with one or more balun(s), wherein the common substrate is an insulating substrate further provided with associated silicon-based CMOS circuitry formed in a thin, highly crystalline silicon layer formed on the insulating substrate. The insulating substrate is selected from transparent crystalline materials such as sapphire, spinel, etc. The common substrate is preferably ultrathin silicon-on-sapphire.

Multi-layer lc resonance balun

Abstract: A multi-layer LC resonance balun includes at least a section of broadside coupled lines connected to an input port and two balanced output ports through transmission lines. Each section of coupled lines has two coupled lines. The first embodiment has at least two sections of coupled lines connected to a transmission line and coupled in parallel with at least one capacitor. The coupled lines are connected to an input port and two balanced output ports. The second embodiment has at least a section of coupled lines coupled in parallel with capacitors and then connected to an input port and two balanced output ports through transmission lines. By means of a multiple layer dielectric structure and meandered coupled lines, the size of the blaun is decreased and the frequency bandwidth is increased.

Lumped constant compensated high/low pass balanced-to-unbalanced transition

Abstract: The invention proposed a lumped constant compensated high/low pass balun (balance line to unbalance line transition). The proposed circuit can be used in microwave integrated circuit (MIC) and monolithic microwave integrated circuit (MMIC) designs. The basic operation principle of the proposed circuit is to use two sets of lumped type high pass and low pass filters to synthesize a microwave balun. The first filter set provides the wide band 180 (phase difference property for the balun circuit). The amplitude imbalance of the balun can be compensated by the other filter set. The advantage of the proposed circuit is to replace the bulky and nonplanar distributed balun or traditional transformer in low microwave frequency range which is very important in MMIC's design.

Integrated balun and transformer structures

Abstract: An on-chip signal transforming device includes a substrate and a first conductive layer above the substrate, wherein the first conductive layer has a plurality of interleaved inductors. The device further includes a second conductive layer above the substrate, wherein the second conductive layer has at least one inductor.

System and method for a radio frequency receiver front end utilizing a balun to couple a low-noise amplifier to a mixer

Abstract: An embodiment of this invention pertains to a fully integrated, highly linear, and power-efficient balun circuit and voltage-to-current converter that interfaces a single-ended low noise amplifier (“LNA”) and a differential mixer. The balun circuit includes components that perform the following functions: provide a load element for the LNA, resonate at the desired frequency of operation to maximize a gain of a single-ended signal output from the single-ended LNA, stabilize the gain of the single-ended signal; convert the single-ended signal to a differential signal, match the impedance between the single-ended LNA and the differential mixer to maximize the power transfer of the differential signal, improve the balance of the differential signal, provide a bias to the LNA, provide a bias for a voltage-to-current converter portion of the differential mixer, and differentially drive a pair of grounded source transistors that linearly convert the differential signal in voltage form to current form. The voltage to current conversion occurs without using a current source in the voltage-to-current converter portion of the differential mixer.

Dual double balanced mixer

Abstract: A double balanced mixer for mixing an RF input signal with a local oscillator signal to provide at an output an intermediate frequency signal with a high third order intercept point. A first and second local oscillator balun receives a local oscillator signal. A first and second RF balun receives a RF signal. A first mixer is coupled to the first local oscillator balun and the first RF balun. A second mixer is coupled in parallel with the first mixer. The second mixer is coupled to the second local oscillator balun and the second RF balun. The parallel coupled mixers provide an intermediate frequency signal. A first intermediate frequency balun is coupled to the first mixer and a second intermediate frequency balun is coupled to the second mixer. The mixer also has increased isolation.

High-frequency module and radio device using the same

Abstract: A high-frequency module includes first to fifth terminals, a high-pass filter, a high-frequency switch, a transmitter-side balun, and a receiver-side balun. The high-pass filter is connected to the high-frequency switch, and the high-frequency switch is also connected to the transmitter-side balun and to the receiver-side balun. The first terminal is connected to an antenna, the second and third terminals are connected to a transmitter circuit, and the fourth and fifth terminals are connected to a receiver circuit.

Low noise architecture for a direct conversion transmitter

Abstract: A low noise direct conversion transmitter architecture without a post-PA filter is described. A high power/low noise differential LO (110), controlled by a near unity divide ratio PLL (112) for re-modulation protection, is coupled a polyphase quadrature generator (120) generating amplitude-balanced and phase-shifted limited differential LO signals. The quadrature mixers (130 and 132) receive the limited differential LO signals and the filtered differential baseband signals to produce up-converted differential signals. The combiner (168) receives the up-converted differential signals and combines them to produce a differential RF transmission signal. A VCA (174) amplifies the differential RF transmission signal, and the resulting differential signal is converted to a single-ended RF transmission signal through a balun (180). A linear amplifier (184) is coupled to the single-ended RF transmission signal for amplification before radio transmission by an antenna (188).

Slot for decade band tapered slot antenna, and method of making and configuring same

Abstract: An antenna apparatus ( 10 ) includes an antenna element ( 12, 412, 512 ) that has conductive material with a recess therein. The recess includes a balun hole ( 36, 536 ), and a tapered slot ( 37, 537 ) communicating at its narrow end with the balun hole. The balun hole is approximately rectangular, has a peripheral edge defined by conductive material, and contains air. The tapered slot has a shape which is optimized as a function of factors that include the balun hole design. Each slot edge follows a predetermined curve other than a first-order exponential curve.

Coaxially-fed tapered slot antenna

Abstract: An improved design of the longitudinal tapered slot antenna is presented which incorporates a tapered coaxial line balun. This transformer type offers large bandwidth, allows for the direct connection of coaxial sources and reduces the complexity of the printed circuit. Experimental results for an antenna prototype are presented.

Modeling of monolithic RF spiral transmission-line balun

Abstract: This paper presents models for monolithic RF spiral transmission-line baluns. The balun consists of a pair of spiral transformers fabricated on high-resistivity silicon. The lumped-element equivalent models are developed. The second-order or higher order models are synthesized from the first-order lumped model. All lumped parameters for the models are extracted from the real physical structures. Simulated behaviors from the second-order models are in good agreement with the measured results within 10% difference.

Balun and groundplanes for decade band tapered slot antenna, and method of making same

Abstract: An antenna apparatus (10) includes an antenna element (12, 412, 512) that has conductive material with a recess therein. The recess includes a balun hole (36, 536), and a tapered slot (37, 537) communicating at its narrow end with the balun hole. The balun hole is approximately rectangular, has a peripheral edge defined by conductive material, and contains air. The tapered slot has a shape which is optimized as a function of factors that include the balun hole design. Each slot edge follows a predetermined curve other than a first-order exponential curve.

A printed dipole for wide-scanning array application

Abstract: The design of a printed dipole for use as a radiating element in array applications is presented. Due to careful control of mutual coupling in the E-plane, the dipole is particularly suitable for wide-scanning active antennas, such as those employed in modern multi-function radar. The printed design is suitable for monolithic integration into an active transmit/receive module. The design features a novel, compact, low-loss and wide-band balun with high immunity to breakdown resulting from high ambient field strength. The latter is particularly important in hostile EM environments such as those encountered by military applications.

Active balun circuit for single-ended to differential RF signal conversion with enhanced common-mode rejection

Abstract: An active balun circuit is provided for single-ended to differential RF signal conversion with enhanced common-mode rejection which suppresses common mode signal and which achieves phase and amplitude balance without sophisticated tuning or compensation methods. The circuit has a single-ended input and balanced output with phase and amplitude balance error less than 2° and 1.2 dB, respectively, measured from 1.5 GHz to 1.8 GHz at 5V supply. When supply voltage drops down to 1.5V, its phase and amplitude balance error remains within 5° and 2 dB, respectively. The circuit achieves a balanced output via an output network which behaves as an impedance matching network for differential mode signal and is grounded for common mode signal. As a result, common mode signal is suppressed and 180-degree phase balance at output is achieved. The circuit has high-linearity (P1 dB in =5 dBm, IIP3=16.6 dBm) and low residual phase noise (<−155 dBc/Hz at 100 kHz and above) which make it suitable as an active balun/buffer amplifier between LO and balanced mixer for base station receiver applications.

Method and system for generating a balanced feed for RF circuit

Abstract: A system and method for generating a balanced feed from an unbalanced feed, which uses a pair of vertically aligned microstrip traces on opposing sides of a printed circuit board to act as a balun and an antenna array using a collinear dipole array.

A thin film type magnetic/dielectric hybrid transmission-line with a large wavelength shortening

Abstract: A novel thin film type hybrid transmission-line device with a magnetic/dielectric multilayer structure was developed. The magnetic/dielectric hybrid micro strip-line consisted of a top aluminum strip line, the CoZrNb/polyimide multilayer structure, and bottom aluminum ground plane on the Al/sub 2/O/sub 3/ substrate. The hybrid microstrip-line exhibited a large wavelength shortening effect. For example, the wavelength ratio of the hybrid transmission-line and free space was below 7%. Therefore, a quarter wavelength distributed constant line device, such as impedance converter, balun and filter, will be miniaturized using the new hybrid transmission-line, because of its large wavelength shortening effect.

Wideband planar log‐periodic balun

Abstract: This paper presents the analysis, design, and performance characteristics of a new planar balun structure. The design is based on the log-periodic antenna theory. The design guidelines, as well as simulation and measured results, are presented. It is shown that the new balun has greater than one octave bandwidth. A comparison to the half-wave balun is also included. The log-periodic balun will find applications in wireless communication circuits or devices such as mixers, amplifiers, and antennas. © 2001 John Wiley & Sons, Inc. Int J RF and Microwave CAE 11: 343–353, 2001.