Showing papers on "Balun published in 1996"

A new planar feed for slot spiral antennas

Abstract: A new planar, wideband feed for a slot spiral antenna is presented and tested at VHF frequencies. Radiation pattern measurements are presented to demonstrate the performance and usefulness of this feed. In contrast to most traditional printed spiral antenna designs, the one presented here incorporates a completely planar balun and feed, making it more attractive for conformal applications.

Multi-port radio frequency signal transformation network

Abstract: A transformation network is provided capable of interfacing between an unbalanced port (110) and a plurality of differently phased balanced ports (120, 130). A balun (165) has a choke (140) and connects the unbalanced port (110) to a balanced pair of nodes. An additional node (145) is provided on the balun. First and second unbalanced phase shift transmission lines (150, 155) have a common ground conductor connected to the additional node (145) of the balun (165). A phase-shifted balanced port (130) is thus provided by center conductors of these first and second unbalanced phase shift transmission lines (150, 155) when the other ends of these transmission lines are coupled to the balanced nodes of the balun (165) and the common ground conductor of these transmission lines is connected to the additional node (145) of the balun.

Slot spiral antenna with integrated balun and feed

Abstract: A slot spiral (18) antenna with a planar integrated balun and feed. The slot spiral is produced using standard printed circuit techniques and comprises a dielectric substrate having a conductive layer which is etched to form the radiating slot spiral. An integrated microstrip feed (16) is included to provide a balanced feed to the slot spiral. Impedance matching is preformed between the microstrip feed and the slotline of the slot spiral to maximize energy transfer. A shallow reflecting cavity is included to limit the spiral radiation to one direction. The described antenna apparatus provides a simple, broadband spiral antenna suitable for incorporating into the skin of a moving vehicle. A covering layer may act as a dielecric lens. Outer parts of the slot spiral may be covered with a lossy absorber for termination. The feed point may be off-center with respect to the spiral.

On-chip transformers

Abstract: Various embodiments of on chip-transformers constructed in separate metal layers in an insulator that serves as a dielectric which is formed on a substrate such as a silicon substrate. Windings with currents flowing in a first direction are constructed in a first metal layer and windings with currents flowing a second direction are constructed in a second metal layer. Windings in the first metal layer are connected to windings in the second metal layer by connectors such as vias. The transformer can be constructed in a balun layout, an autotransformer layout, a layout with the secondary separated from the primary, a layout with the secondary separated the primary and rotated with respect to an axis of the primary, a layout in which the transformer is a two stage transformer and with the first stage constructed orthogonal to the second stage, or a transformer in which the windings are constructed in a toroidal layout.

Cascaded surface wave device filters providing balanced and unbalanced signal connections

Abstract: A cascaded surface wave device filter comprises two 2-pole surface wave device filters connected in cascade. The 2-pole filters each provide a balun function between balanced and unbalanced signal connections, and have either their unbalanced or their balanced signal connections interconnected in the cascade to reduce electromagnetic feedthrough and improve spurious mode suppression. The 2-pole filters are conveniently longitudinally coupled double mode surface wave resonators which are described, or transversely coupled double mode surface wave resonators. Higher order filters can be provided by connecting further 2-pole filters in the cascade. The cascaded filter is particularly useful for filtering at radio and intermediate frequencies in cellular radio equipment.

Printed guanella 1:4 balun

Abstract: A Guanella 1:4 balun is made capable of handling frequencies in the gigahertz range by printing its transmission lines on a microwave laminate. The resulting balun has a largest dimension substantially smaller than one free space wavelength throughout a 20:1 usable frequency range.

A miniaturized lumped-distributed balun for modern wireless communication systems

Abstract: The reduction in size of RF signal processing components is an important part of the miniaturization and cost reduction of wireless communication systems. A balun is a crucial component in most wireless communication systems. In this paper we describe research aimed at reducing the size and manufacturing complexity of printed baluns. A design utilizing distributed microstrip coupled lines and lumped capacitors is presented. The structure has the major advantage of being considerably smaller than the quarter-wavelength size of conventional "planar" baluns. This work is unique in that simulated results are presented which describe the effects and tradeoffs of changing important design parameters. The paper then describes performance-enhancing changes to the design. Excellent response characteristics for coupled circuit performance are shown to result.

A novel HBT active transformer balanced Schottky diode mixer

Abstract: This paper describes a unique HBT active transformer balun which has been monolithically integrated with a GaAs Schottky diode ring quad to construct a double balanced mixer which can operate from DC to >2 GHz. The HBT active balun transformer achieves

A broadband planar monolithic ring mixer

Abstract: This paper reports the development of a mixer having RF and LO bands of 3 to 11 GHz and an overlapping IF of 1 to 11 GHz. This was achieved through the use of novel planar spiral RF and LO baluns and a new type of four-wire IF balun. We believe that this is the broadest-bandwidth planar monolithic mixer having an overlapped IF reported to date.

Compensated ring mixers

Abstract: A compensated mixer including a radio frequency (RF) balun (18) through which RF signals are transferred, and a local oscillator (LO) balun (14) for receiving an LO signal. In an exemplary implementation the mixer further includes a diode ring quad circuit (12) for mixing RF signals received by the RF balun (18) with the LO signal received by the LO balun (14). During operation the diode ring quad circuit develops, between the first and second nodes therein (50, 52), a capacitive reactance arising from switching at the LO frequency. The mixer further includes a compensation inductor (56), connected between the first and second nodes (50, 52), for cancelling the effect of the capacitive reactance at the LO signal frequency.

Mixer constructed from thick film balanced line structure

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.

A new balanced-unbalanced type RF-band SAW filter

Abstract: A new balanced-unbalanced type RF-band (950 MHz) surface acoustic wave (SAW) filter for use in portable telephones is presented. This SAW filter has unbalanced input and balanced output terminals. Balanced-unbalanced type SAW filters having a pass-band at 950 MHz were fabricated. The obtained results showed excellent characteristics such as low insertion loss, wide bandwidth, and small VSWR. Using the SAW filter, one can realize balanced-type RF circuits in portable telephones.

Multi-layer printed wiring board having integrated broadside microwave coupled baluns

Abstract: A microwave broadside coupled balun integral in a multi-layer printed wiring board formed by broadside coupled conductors embedded in the multi-layer printed wiring board. The balun may be used to form components which are integrated into the multi-layer printed wiring board, such as a microwave mixer formed by two of said broadside coupled baluns embedded in a multi-layer printed wiring board and connected to a diode ring quad.

Folded U-Shaped Microwire Technology for Ultra-Compact Three-Dimensional MMIC's

Abstract: A microwire technique has been developed for fabricating three-dimensional (3-D) structures for use in ultra-compact GaAs monolithic microwave/millimeter wave integrated circuits (MMIC). By folding metal into a U-shapedl wall and burying it in a relatively thick polyimide insulator, vertical microwires can be made with greatly reduced process complexity. This technique also offers process compatibility with multilevel interconnects. In this paper, the fundamental characteristics of the proposed Ushaped microwire are dkcussed and its applications to 3-D passive elements and circuits are demonstrated. The characteristics of the U-shaped microwires are almost the same as those of I-shaped microwires and can be accurately estimated and designed by using numerical analysis. The fabricated and designed transmission lines are one-half to one-third the size of conventional lines with the same transmission loss, and if the microwire is also used as a shielding wall, the occupied area can be made much smaller. Miniature inductors made of vertical U-shaped microwires exhibit a self-resonance freqnency as high as that of conventional inductors, with one-half the size and offer a great advantage in L- or S-band applications. A fabricated miniature wideband 3-D balun had an insertion loss of 1.5 + 1 dB at frequencies from 10 to 30 GHz, and an amplitude and phase balance of 2 dB and 5/spl deg/, respectively.

Antenna assembly with balun and tuning element for a portable radio

Abstract: Arms (310, 320, 330, 340) of an antenna element are connected to a balanced-unbalanced conversion network (510) at a feed point of excitation to provide an antenna assembly. Characteristics such as size of the antenna assembly are improved by providing a tuning element near connections (610, 620) to a feed point of excitation. The tuning element (410) is electrically connected to one of the arms (330) but is disposed with a gap between a neighboring arm (320). A gap may also be provided between the tuning element (410) and a feed point of excitation. The arms and tuning element are preferably thin metallic arms formed on an elongated dielectric tube (210) in the preferred construction of the invention. The balanced-unbalanced conversion network (510) may also be disposed within the elongated dielectric tube (210) according to the preferred construction.

Low power dual sampler utilizing step recovery diodes (SRDS)

Abstract: A low power dual sampler including two sampler switches with a step recovery diode (SRD) in each sampler switch A local oscillator (LO) signal is provided through a power amplifier and transformer to baluns in the sampler switches without utilizing a power splitter, providing limited power loss to each balun Each balun is configured to provide the LO signal to terminals of the SRD in a sampler switch without providing a termination to SRD impulses Each sampler switch further includes series diodes connected across the terminals of each SRD switch with a junction of the series diodes connected to receive an RF signal, and the terminals of each SRD connected for providing an IF signal To limit phase shift between SRD impulses, a temperature compensation circuit provides a DC offset voltage to each SRD In one embodiment, each temperature compensation circuit includes an operational amplifier having a noninverting terminal coupled to a terminal of an SRD, an inverting terminal connected by a first resistor to ground, and an output connected by a second resistor to the inverting terminal and by a third resistor to the non-inverting terminal To provide isolation between the sampler switches, a capacitor providing a high impedance to the LO signal and a low impedance to RF signals is connected at the interconnection of the sampler switches

Floating fet mixer

Abstract: A floating FET mixer (1) comprises: a field effect transistor, FET, (2) having a gate (11), a drain terminal (4) and a source terminal (5), an LO port (10) at which an LO signal from a local oscillator is coupled to the gate (11), primary windings (9) of a balun (3) across the drain terminal (4) and the source terminal (5), secondary windings (8) of the balun (3) coupled at its opposite ends to ground and an RF port (7), respectively, a center tap (12) on the primary windings (9), and a series biasing element (20) on the gate (11) biasing the FET (2) near pinch off.

A novel compact balun structure for multilayer MMICs

Abstract: A novel compact MMIC balun and its design methodology has been developed, and turns out to combine the good balance of a MARCHAND-type balun with the compactness of a MMIC transmission line transformer. Analysis using accurate quasi-static as well as parallel independent full-wave simulation shows good performance. Application of this component is seen for example in microwave and RF frequency conversion and power amplifiers. A novel compact balun structure for multilayer MMICs M Engels and R H Jansen Aachen University of Technology (RWTH), Dept. of El. Engineering, ITHE, Kopernikusstr.16, D-52074 Aachen, Germany. Abstract A novel compact MMIC balun and its design methodology has been developed, and turns out to combine the good balance of a MARCHAND-type balun with the compactness of a MMIC transmission line transformer. Analysis using accurate quasi-static as well as parallel independent full-wave simulation shows good performance. Application of this component is seen for example in microwave and RF frequency conversion and power amplifiers.

Layer-built balun transformer

Abstract: PROBLEM TO BE SOLVED: To adjust electromagnetic couplings between strip lines easily and, further, reduce the size. SOLUTION: A layer-built balun transformer 1 is composed of a dielectric sheet 2b which has extraction electrode 3 on its surface, dielectric sheets 2c, 2d, 2f and 2g which have 1/4-wavelength strip lines 4, 5, 8 and 9 on their surfaces respectively and dielectric sheets 2a, 2e and 2h which have grounding electrodes 12, 13 and 14 on their surfaces respectively. The strip lines 4 and 5 are made to face each other with the sheet 2c therebetween to form an electromagnetic coupling. The strip lines 8 and 9 are made to face each other with the sheet 2f therebetween to form an electromagnetic coupling. The end part 4a of the strip line 4 and the end part 9a of the strip line 9 are electrically connected to each other through external electrodes.

Over-30-GHz limiting amplifier ICs with small phase deviation for optical communication systems

Abstract: For a high-speed limiting amplifier with small phase deviation, a new design technique using a uniplanar passive balun and a narrow-band matching network is proposed It is revealed that a device with small bias-dependence of parasitic capacitances, such as a high electron mobility transistor (HEMT), and a differential operation using passive baluns enables phase deviations at very high frequency to be reduced Furthermore, suppressing harmonics can reduce phase deviation in a limiting amplifier, which operates in the highly nonlinear region To verify these design techniques, two types of limiting amplifier ICs using an InP HEMT and AlGaAs/GaAs BCT technology were designed and fabricated These IC's feature narrow-band matching circuits for input and output using transmission lines and uniplanar CPW-slot transition baluns for differential signals The devices achieved high frequency operation of over 30 GHz with small phase deviations

Cascaded surface wave device filters

Abstract: A cascaded surface wave device filter comprises two 2-pole surface wave device filters connected in cascade. The 2-pole filters each provide a balun function between balanced and unbalanced signal connections, and have either their unbalanced or their balanced signal connections interconnected in the cascade to reduce electro-magnetic feedthrough and improve spurious mode suppression. The 2-pole filters are conveniently longitudinally coupled double mode surface wave resonators which are described, or transversely coupled double mode surface wave resonators. Higher order filters can be provided by connecting further 2-pole filters in the cascade. The cascaded filter is particularly useful for filtering at radio and intermediate frequencies in cellular radio equipment.

Phase cancellation in a multi-output distribution amplifier at crossover frequency

Abstract: A multi-output distribution amplifier includes a forward amplifier and a reverse amplifier and multiple outputs. The forward and reverse paths are separated utilizing low and high pass filters. The geometric mean frequency between the respective pass bands of the high and low pass filters is known as the crossover frequency. A circuit for providing a 180 degree phase reversal such as a balun transformer is connected in series with one (in a dual output arrangement) or half the reverse paths of an arrangement involving three or more forward or reverse paths to improve crossover isolation. For example, in a typical dual output distribution arrangement where the amplifiers are not padded, close to 20 dB of crossover isolation improvement is accomplished by simply connecting a balun transformer in series with one or the other of the low pass filters connected to one or the other forward direction output. At a minimum, a 6 dB improvement can be achieved.

Rf transformer using multilayer metal polymer structures

Abstract: A transformer for high frequency applications having a multilayer thin film structure and a dielectric material disposed between coils increases the inductive coupling between the coils while at the same time reducing the capacitive coupling between the coils of the transformer. A glass substrate (201) has a first metal spiral (301) deposited thereon, and a layer of polymer insulator (601) is deposited thereon encapsulating the first metal spiral. A second metal spiral (701) is deposited on the layer of polymer and the process continues with a next layer of polymer material. The interconnection of the metal spirals to one another in the different layers is effected by the use of selectively etched grooves having vias (902) deposited therein. The present invention is specifically drawn to a balun transformer. The use of the polymer preferably BCB as the dielectric has the functional advantage of very low loss due to absorption at microwave and rf frequencies, and yet this insulator allows for excellent inductive coupling while reducing greatly the capacitive coupling among the various layers of the device.

An improved planar balun design for wireless microwave and RF applications

Abstract: The high frequency balun network is a vital component in the realization of certain RF and microwave system topologies, especially in wireless communication system architectures. This paper describes an improved compact coupled microstrip line design for use primarily in the exploding portable wireless market. The two main advantages of the design are that its size is a fraction of the standard /spl lambda//4 coupled line design, and that it exhibits an extremely tight coupling of /spl sim/4 dB. The design technique is illustrated by presentation of computed and measured data on a /spl sim/0.9 GHz realization developed for wireless applications.

Triple-balanced passive transmission fet mixer

Abstract: FET mixer comprising two switching circuits, each comprising two series connected FET transistors (Q1, Q2; Q3, Q4); a local oscillator balun (T1A, T1B) having a single two terminal input port and two terminal output ports, each output port being connected to the together connected bases of the transistors (Q1, Q2; Q3, Q4) of one of the switching circuits; an RF balun (T2A, T2B) connecting the RF input signal to the drains of the transistors of the switching circuits; an IF balun (T3A, T3B) and a DC bias circuit (45). The mixer needs only a low local oscillator power, provides for a partial cancellation of the nonlinearity distortion imposed on the RF signal and has a reduced intermodulation distortion.

A Ka-band GaInP/GaAs HBT double balanced upconvert mixer using lumped element balun

Abstract: A Ka-band GaInP/GaAs HBT double balanced upconvert mixer has been designed and fabricated. This circuit is to be used in a multifunction T/R module for local multipoint distribution systems (LMDS) which include both analog and digital transmission. A conversion gain of 1 dB, and an output power of -10 dBm from 27 GHz to 30 GHz for an LO input power of 10 dBm at 26 GHz were measured. The LO isolation to the output was measured to be 20 dB. These results are the best reported at Ka-band for a mixer using transistors from digital HBT library.

Filter enhancement using input-to-output ground isolation and shielding

Abstract: A method and apparatus for filter enhancement in an electrical system (8) is provided The electrical system (8) includes an input circuit (10) having a filter (14) and an output circuit (20) having a filter (24) An input conductive enclosure (12) and an output conductive enclosure (22) protect the electrical system (8) from field coupling between the input circuit (10) and the output circuit (20) A choke balun (26) is connected between the input circuit (10) and the output circuit (20) to also eliminate conductive coupling The elimination of unwanted coupling enhances the performance of the electrical system (8) by achieving greater stopband attenuation

Quasi-optical log-periodic antenna SIS mixers for the 100 GHz band

Abstract: We designed and tested a quasi-optical SIS mixer that incorporates a substrate lens for the 100 GHz band. The mixer uses a planar self-complementary log-periodic antenna with an integrated tuning circuit. The antenna has a frequency independent impedance of around over several octaves. The tuning circuit consists of two SIS junctions connected in parallel through a superconducting stripline inductor for tuning out the junction capacitances and a impedance transformer for matching the junction resistance to the antenna impedance. The SIS junctions are and have an area of and a current density of . The IF output from the mixer is brought out in a balanced way at each edge of the antenna, and is coupled to a cooled low-noise amplifier through a balun transformer by using a hybrid coupler. A double-sideband receiver noise temperature less than 130 K was measured from 85 to 110 GHz. The best noise temperature was 90 K at 101 GHz, which is the same as for waveguide receivers.

Optical intensity modulator using inverted slot line at 60 GHz

Abstract: The inverted slot line (ISL) structure which has been proposed for millimeter wave LiNbO/sub 3/ optical modulator is found to be very simple in structure, and also is capable of achieving perfect velocity matching between carrier and modulating waves. This paper describes the development of a Mach-Zehnder Ti-diffused LiNbO/sub 3/ optical intensity modulator using the ISL at 60 GHz. To launch millimeter waves into the ISL structure two types of transitions have been developed successfully. In one type, a balun which is made from semirigid coaxial cable is used to feed millimeter waves into the ISL. In another type, nonradiative dielectric (NRD) waveguide, which can provide the total integration of the modulator with millimeter wave integrated circuits, is used to excite the ISL structure ensuring minimum transition losses. Optical response of 0.17 W/sup -1/ could be obtained at 60 GHz using a Mach-Zehnder interferometer with a rather poor extinction ratio of 5 dB at an optical wavelength of 0.633 /spl mu/m.

High performance mixer and method of designing 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.