Showing papers on "Balun published in 1989"

Hybrid-balun for splitting/combining RF power

Abstract: An in-phase hybrid and a balun in a single stage built with inexpensive coaxial cable which splits or combines RF power and simultaneously performs a balanced-to-unbalanced impedance transformation.

Planar broadband FET balun

Abstract: Three active FET baluns, using resonant, reactive and resistive/reactive compensation are disclosed suitable for monolithic implementation. A single balanced mixer configuration including a resistive/reactive active FET balun coupled with a pair of single ended FET mixers in a push pull configuration is disclosed which is also suitable for monolithic implementation.

VHF DC-DC power supply operating at frequencies greater than 50 MHz

Abstract: A DC to DC power supply including an RF driver circuit for providing an RF output drive signal having a frequency greater than about 50 MHz, power amplifier circuitry responsive to the RF output drive signal and a DC voltage supply for providing an amplified AC output, and an impedance transforming circuit such as a balun transformer for transforming the AC amplified output to an impedance transformed AC signal. The transformed AC signal is provided to a rectifying circuit which provides a DC output. A feedback regulation control circuit provides for regulation of the power supply output voltage. The DC to DC power supply is advantageously implemented with printed microstrip or stripline passive components.

Monolithic multilayer planar transmission line

Abstract: A multilayer planar transmission line (10) can be fabricated as a monolithic structure with series/shunt-connected components for integration in an MMIC device. The multilayer planar transmission line (10) includes a first transmission line structure (TL1) formed by a top conductor (14) and an interlevel conductor (16) separated by an interlevel dielectric (18). This structure is formed on one planar surface of a substrate (12), and a ground plane reference (20) is formed on the opposing surface, yielding second and third transmission line structures (TL2, TL3) formed by the groundplane reference and, respectively, the interlevel conductor (16) and the top conductor (14). The interlevel dielectric layer (18) is significantly thinner than the substrate dielectric, so that the first transmission line (TL1) is tightly coupled, and substantially unaffected by parasitics between the bottom of the interlevel conductor (16) and the groundplane reference (20). In an exemplary embodiment, a monolithic multilayer planar transmission line network is configured as a Marchand-type balun (30). A top conductor (34) is configured in two continuous sections (Z1 and Z2), and an interlevel conductor (36) is configured in two separate sections (ZS1) and ZS2), separated by a balance point gap (BP). This configuration forms series transmission lines (Z1 and Z2) shunt-connected to a second pair of series transmission lines (ZS1 and ZS2). With the appropriate configuration of the top and interlevel conductors (34, 36), impedance values can be established to yield a balanced signal output at the balance point gap (BP).

Dual directional bridge and balun used as reflectometer test set

Abstract: A test set for use in measuring S-parameters with a network analyzer includes a first directional bridge, a second directional bridge and a single balun with two outputs mounted in an RF housing. A test signal from an RF signal source is transmitted through the test set to a device under test. The first directional bridge separates a signal from the device under test and the test signal, and provides the signal from the device under test to a coupled port. The second directional bridge separates the test signal and the signal from the device under test and provides the test signal to a reference port. The balun includes a coaxial transmission line with its outer conductor grounded at an intermediate location to define first and second balun sections. Ferrite beads are mounted on each of the balun sections. The ends of the first and second balun sections are coupled to the first and second directional bridges, respectively.

Analysis of rectangular spiral transformers for MMIC applications

Abstract: Multidielectric planar structures such as transformers and triformers are analyzed by cascading multidimensional chain matrices. The distributed-line model facilitates the use of these elements in microwave monolithic integrated circuits (MMIC) applications as wideband transformers and baluns. High-speed routines suitable for inclusion in computer-aided design packages for desktop PCs are implemented and used to calculate S parameters. Wideband MMIC triformers are fabricated and measured, showing good agreement between theory and measurement over the frequency range 1-10 GHz. >

Enhanced coupled, even mode terminated baluns, and mixers and modulators constructed therefrom

Abstract: A balun section formed of a pair of transmission lines connected between separate pairs of corresponding input and output terminals with a pair of capacitors connected in series between the output terminals and another transmission line connected in series with a resistor between the circuit ground and the interconnection between the pair of capacitors. A multisection balun is constructed from a plurality of such balun sections connected in cascade. In one embodiment, the outputs of a pair of multisection baluns are supplied to a circuit such as a mixer or the like.

Multi-mode antenna system having plural radiators coupled via hybrid circuit modules

Abstract: A hybrid circuit module having first and second pairs of input terminals and four output terminals. First, second, third and fourth baluns each include first and second transmission line wires. The baluns are configured between the input and output terminals to isolate sources when placed across pairs of input and output terminals. An antenna system is formed with the hybrid circuit module and a plurality of radiators. The circuit module may be configured to simultaneously generate or receive two or more independent radiation patterns. A method is provided for feeding a multiarm antenna structure with a hybrid circuit network. The method includes the steps of symmetrically positioning a conductive element with respect to all of the arms, and coupling terminals of the antenna arms to the network through a conductive element. Alternately the second terminals may be electromagnetically coupled to the network without requiring the conductive element. Generally the invention enables simultaneously feeding of antenna arms with two or more independent signals in order to transmit or receive multiple independent radiation patterns.

A new coplanar waveguide/slotline double-balanced mixer

Abstract: A novel design concept for a broadband planar mixer, using single-sided substrate processing, is presented. Through the use of a diode crossover quad and coplanar waveguide/slotline baluns, the need for via holes and back metallization has been eliminated. The design offers a potential reduction in production costs compared to other mixer types. The planar construction is highly reliable and lends itself to modular MIC (microwave integrated circuit) applications. A sample mixer operating at 6-18 GHz with a fixed IF (intermediate frequency) of 1 GHz demonstrates a 5.0- to 8.5-dB conversion loss. >

High permitivity dielectric microstrip dipole antenna

Abstract: A miniature microstrip dipole antenna is constructed on a high permitivity dielectric substrate for compactibility with microwave monolithic integrated circuit (MMIC) technology. The antenna comprises two dipole arms coupled to opposite faces of the substrate. The dipole arms are coupled to a microstrip transmission line through a tapered balun. The tapered balun comprises two conductors on opposite faces of the substrate which are coupled to corresponding dipole arms. The conductors are separated laterally (with respect to the width of the face of the substrate) a calculated distance, and are gradually tapered. This allows the balun to efficiently transform unbalanced signals at the microstrip transmission line to balanced signals at the plurality of dipole arms. Alternatively, the balun allows balanced signals at the dipole arms to be efficiently transformed to unbalanced signals at the microstrip transmission line. To achieve additional radiation directivity, a ground plane is coupled to and parallel with a back face of the substrate. By using a high dielectric substrate, the cavity formed between the substrate and the ground plane is relatively very shallow.

RF power combiner using baluns

Abstract: An RF power combiner combines the power of several microwave high power FET amplifiers. A plurality of baluns which convert a balanced transmission line to an unbalanced transmission line and have outputs which are 180° out of phase from each other may be connected at the inputs and the outputs of the FETs. This connection allows for very high output power while matching impedances of the input and the output of the power combiner. Additionally, loss in the output circuit can be minimized by connecting equi-phase outputs of the FETs in a parallel/push-pull manner.

Open field test site reference antenna with integral battery powered signal generator

Abstract: A calibrator circuit for a self-contained device for vertification of open field test site accuracy. This device generates a broadband width of discrete frequencies from 10 MHz to 1000 MHz which is then radiated into space. The circuit contains a power supply subcircuit, an oscillator subcircuit which generates an output signal rich in harmonics, an antenna radiating element and a balun network to couple the output from the oscillator subcircuit to the antenna element.

A Printed Circuit Folded Dipole with Integrated Balun

Abstract: : This report documents the design and testing of a printed circuit folded dipole with a unique double-tuning balun as feed. Simple transmission line theory is used to analyze the balun structure, whereas the method-of- moments and conformal mapping techniques are used to analyze the dipole impedance and step-up ratio. Two dipoles were then fabricated on substrates of different dielectric constant material. The antenna designs were then tested for impedance match and radiation characteristics. First, SWR measurements were made on the two dipoles that were fabricated, and the results compared to theory. Next, antenna patterns are taken of the folded dipoles at several frequencies over the operating band to determine any frequency dependence of the patterns. Finally, cross-polarization patterns are presented. (RH)

Mixer having balun mounted to a support block

Abstract: A diode type mixer includes a diode circuit and a balun transformer, and is used in a frequency convertor which converts a 1-GHz primary intermediate frequency signal to a secondary intermediate frequency signal in a satellite broadcast receiver. The balun transformer (5) is fixed to a support block (10), and the terminals of the balun transformer (5) are connected to the stems (11) of the support block (10). Hollow coils (12 and 13) are connected between the ground terminal and the balanced terminals of the support block (10). The high frequency characteristics of the mixer can be improved, and productivity in mass production can be enhanced.

Noise elimination filter

Abstract: PURPOSE:To make even a normal mode noise on a low frequency region removable effectively without an exclusive choke coil and a capacitor of large capacity, by forming a structure with no decrease in leakage inductance even if a balun choke is located in a metal case made of a magnetic material CONSTITUTION:A balun choke 1 is provided with a rectangular magnetic core of a closed magnetic path which is divided into two regions 2a, 2b on alternate long and short dashes line positions in the direction of its long side, and each one of windings 3, 4 is wound on three sides of each region in the direction that two species of magnetic flux generated by their forward and backward currents are canceled to each other This balun choke 1 is located in a metal case made of a magnetic material Since each one of two species of the magnetic flux generated by the windings 3, 4 travels through the three sides of the magnetic core 2, two species of leakage flux 5 and 6 pass to short long sides of the magnetic core 2, as shown in a figure, inside loops of the magnetic core 2

Distributed parameter approach to pulse response analysis of n:1 balun transformers

Abstract: Balun transformers of an arbitrary turns ratio of n:1 were considered as two asymmetrically coupled transmission lines, whose four-port fundamental equations were introduced. Equivalent circuits of isolation-type and transmission-line-type balun transformers were derived for the calculation of pulse rise-time and flat-top responses. These transformers have two output ports, and the reason for this two-output-port voltage asymmetry was theoretically explicated by deriving the equivalent circuits. To improve the balance of the balun transformer outputs, compensation methods were presented. Pulse rise-time responses were evaluated for the parameters associated with the transformer parameters and terminations. Experimental balun transformers were constructed, the output voltage balance of which was much improved by the compensation method, and high-speed pulse rise-time responses were obtained. >

Arrangement for operating a symmetrical rf-antenna

Abstract: To operate an RF antenna of a nuclear spin tomograph which is connected to an unbalanced line and in which a sheath wave barrier is provided between the RF antenna and the line, the inductance L of the sheath wave barrier is designed, according to the invention, as a toroid (2). In this embodiment, a low-leakage sheath wave barrier is obtained which is particularly suitable for circularly polarised resonators. It suppresses difference currents caused by imbalances and consequently acts as a balun at the same time.

Abstimmverfahren und -einrichtung fuer kapazitaetsmessbruecken

Abstract: For detecting small variations in capacitance in a specimen 3 under test, a HF generator 1 supplies HF current through a quadruple balun transformer 2 to a parallel resonant circuit including the specimen 3, a capacitance diode 5 and an inductor 7, and a pre-amplifier 9 is connected to a phase sensitive rectifier (not shown) to produce an output representing capacitance variation of the specimen 3. Bias voltages U1, U2 are applied to the specimen 3 and the capacitor 5 and a compensating HF current is applied to the pre-amplifier 9 with 180 DEG phase shift via FET 8 controlled by a voltage U3. A gate 11 under the control of U4 switches the input of pre-amplifier 9 to compensate for relaxation time effects of the specimen 3. Balance of the apparatus is achieved by firstly applying a control voltage U4 to FET 11 to reduce the gain of pre-amplifier 9. Control voltage U5 is then adjusted to achieve balance.

A 2-20 GHz dual channel receiver with 2-6 GHz IF

Abstract: A dual-channel 2-20-GHz receiver with a 2-6-GHz IF (intermediate frequency) has been designed and developed to give conversion gain and good LO (local oscillator) and RF rejections at intermediate frequencies. It utilizes nine MMIC (monolithic microwave integrated circuit) chips and has an 8-to-12 GHz MESFET voltage-controlled oscillator. The receiver uses a unique planar balun for the double balanced mixer. >

A New Coplanar Waveguide /Slotline Double-Balanced Mixer

Abstract: A new double-balanced MIC mixer design is presented Through the use of a diode crossover quad and coplanar waveguide/slotline baluns, the need for via holes and back metalization has been eliminated A samplemixer with 618 GHz RF and lGHz IFdemonstrates a 50 to 85 dB conversion loss

Interconnection line for microwave integrated circuit substrate

Abstract: PURPOSE:To obtain an MIC substrate interconnection line stable against temperature change without being affected by a ground conductor by connecting a three-wire coplanar balun between both ends of a balanced line. CONSTITUTION:A 1st three-wire coplanar balun 7 whose high frequency characteristic is excellent converts the unbalanced mode of an input strip line into the balanced mode. A 2nd three-wire coplaner balun 8 converts the mode from the balanced mode into the unbalanced mode again. The length of the 1st and 2nd three-wire coplanar lines 7, 8 is lambda0/4. Moreover, the balanced line section of the balanced line 9 is formed by a suspended line. Thus, the current of the equal width and opposite phase flows respectively from the center conductor to the ground line in the unbalanced mode part at both ends, but a current flows between a couple of lines in the balanced line part 9 and no ground current flows, then the effect of the ground conductor is eliminated.

Diode mixer circuit

Abstract: PURPOSE:To improve a 2nd order cross modulation characteristic due to a diode by detecting the power of a local oscillator and applying reverse bias to the diode to a bipolar voltage in response to the output voltage. CONSTITUTION:A signal from a VCO 20 becomes two balanced outputs whose phase is inverted to each other by a balun 21 and the result is fed to diodes 24, 25. On the other hand, an RF signal enters an RF port 27 and a sum or difference component due to the nonlinear distortion of the diodes 24, 25 is extracted from the IF port 28 as the IF signal. In this case, a DC voltage is obtained by a detection circuit 29 in response to the output power of the VCO 20, the bipolar but identical voltages are extracted from a generation circuit 30, a positive voltage is fed to the cathode of the diode 25 via a resistor 32 and fed to the anode of the diode 24 via a resistor 31, the resistor 33 is connected to apply reverse bias to the diode and the operating point is decided to improve the 2nd order cross modulation distortion.

Unipolar-bipolar converting transformer

Abstract: PURPOSE:To enable eliminating induction noise caused by transversal current, without adding a balun type transformer, by providing a core, two primary windings wound around the core, a secondary winding wound around the core, and two balun windings wound around the core. CONSTITUTION:Driving transistors 17, 18 are connected to the respective other ends of primary windings 11, 12. When the transistors are turned ON/OFF, and currents flow intermittently through the primary windings 11, 12, a detection voltage generates in a detecting winding 14, in accordance with the above currents, and this voltage is supplied to a detection circuit. In the secondary winding 13, an induced voltage generates, and this voltage is supplied to each end of balun windings 15, 16. After induction noise component caused by transversal current is eliminated by the balun windings 15, 16, the voltage generated in the secondary winding 13 is output from the other end of each of the balun windings 15, 16, and supplied to an output circuit. Since the balun windings 15, 16 are wound around the core 10 of a transformer, the induction noise caused by the longitudinal current can be reduced without adding a balun type transformer.