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Showing papers on "Balun published in 1997"


Patent
14 Feb 1997
TL;DR: In this paper, a linear RF power amplifier employs push-pull pairs of high voltage mosfets with temperature sensors mounted in the air inlet path and on the spreader plate of the heat sink.
Abstract: A linear RF power amplifier employs push-pull pairs of high voltage mosfets. A minimum of transformers is employed, with an impedance matching transformer feeding an input balun supplying the input signal in push-pull to the gates of the mosfets. The drains are coupled to balanced legs of an output balun, followed by an output impedance matching transformer. Thermal sensors are employed for control of gate bias and also for control of drain voltage. The temperature sensors are mounted in the air inlet path and on the spreader plate of the heat sink. An aluminum or fiberglass strap is used to press the transistors against the spreader plate thereby ensuring good thermal contact with the transistor dies.

101 citations


Patent
Ichiro Abeno1, Hideki Ikuta1
08 Sep 1997
TL;DR: In this article, a phase modulator having a Gilbert cell mixer was used in frequency ranges from a microwave frequency band of several GHz to a millimeter wave band of many 10 GHz.
Abstract: A phase modulator having a Gilbert cell mixer can be used in frequency ranges from a microwave frequency band of several GHz to a millimeter wave band of several 10 GHz. Two output signals Vout1, Vout2 from the Gilbert cell mixer are supplied to balanced input terminals of a balanced-to-unbalanced converter, which produces a phase-modulated output signal Vout from an unbalanced output terminal thereof. Even when a differential amplifier comprising FETs Q1, Q3 and a differential amplifier comprising FETs Q2, Q4 do not operate symmetrically, the phase modulator generates phase-modulated output signals that have the same amplitude as each other and are in opposite phase to each other. With the Gilbert cell mixer comprising FETs, the phase modulator can be used in the frequency ranges described above. If the balanced-to-unbalanced converter is in the form of a planar circuit, then the phase modulator may be implemented by an MMIC.

72 citations


Patent
13 Feb 1997
TL;DR: Balanced-unbalanced ("baluns") as discussed by the authors is a technique used to couple each receive coil to its lead cable connecting it to the MR imaging electronics to optimize signal-to-noise ratio of the received signal.
Abstract: One or more flexible magnetic Resonance (MR) receive coils are constructed of a flexible material and connected to a flexible base to produce a module. Each module has the coils overlapping by a predetermined amount to minimize coupling between the coils. The modules may be connected by attachment means placed at predefined locations to cause overlap of adjacent coils such that the coupling is minimized. Balanced-unbalanced ("baluns") may be used to couple each receive coil to its lead cable connecting it to the MR imaging electronics. The baluns effectively isolate the coils from the cables and each other to optimize signal-to-noise ratio of the received signal.

57 citations


Journal ArticleDOI
TL;DR: In this paper, a lumped element balun structure for both monolithic and hybrid circuits was proposed, which utilizes two filters to compensate the amplitude and phase errors at the two balance outputs of a traditional out-of-phase power splitter.
Abstract: We report a novel lumped element balun structure for both monolithic and hybrid circuit applications. The proposed structure utilizes two filters to compensate the amplitude and phase errors at the two balance outputs of a traditional out-of-phase power splitter. This circuit requires no multilayer or suspended substrates techniques; therefore, wide applications on many circuits operated especially, in the low microwave band, are expected. Two monolithic microwave integrated circuit (MMIC) mixers were built to demonstrate the electrical feasibility.

55 citations


Patent
04 Dec 1997
TL;DR: In this article, the authors proposed a method to provide a device which can be miniaturized in height/width directions by providing plural logarithm period dipole parts excited from two parallel lines transmitting radio waves from a micro strip line in accordance with respective necessary frequency bands.
Abstract: PROBLEM TO BE SOLVED: To provide a device which radiates large power and which can be miniaturized in height/width directions by providing plural logarithm period dipole parts excited from two parallel lines transmitting radio waves from a micro strip line in accordance with respective necessary frequency bands and reflecting the radiated radio wave of the logarithm period dipole part so as to radiate the radio wave. SOLUTION: An input signal is inputted to the micro strip line 12 from a feeder circuit through a connector. The input signal is transmitted through the micro strip line 12 and it is transmitted through a balun 13. Then, it is naturally converted into a signal transmitted through the two parallel lines 14. The converted signal is transmitted through the two parallel lines 14 but a metallic reflection board 17 and the two parallel lines 14 are insulated at a position where they cross the metallic reflection board 17 by a hole provided on the metallic reflection board 17. The signal is transmitted and it is excited in the first necessary frequency band at first and it is not resonated and is not excited in the second necessary frequency band.

53 citations


Journal ArticleDOI
TL;DR: In this paper, the authors report the development of completely uniplanar broadband balanced push-pull FET amplifiers using slot line and coplanar waveguide, which employ broad-band uni-planar baluns to achieve the pushpull function over a wide bandwidth.
Abstract: We report the development of completely uniplanar broadband balanced push-pull FET amplifiers using slot line and coplanar waveguide. The amplifiers employ broad-band uniplanar baluns to achieve the push-pull function over a wide bandwidth. One amplifier, designed in the unconditionally stable region, exhibits a gain of 3.5-5 dB over the frequency range of 5.4-10 GHz and an output 1-dB compression point of 19 dBm at 10 GHz. The other amplifier was designed in the potentially unstable range and achieves a high gain between 10-11 dB from 2 to 4 GHz and an output 1-dB compression point of 17 dBm at 4 GHz. These results show the feasibility of the push-pull FET amplifier configuration using uniplanar technology for microwave and millimeter-wave integrated circuits and systems.

52 citations


Patent
25 Nov 1997
TL;DR: In this paper, an unbalanced-to-balanced converter (balun) consisting of three distributed-constant lines was proposed. But the converter was not designed for wireless networks.
Abstract: An unbalanced-to-balanced converter (balun) comprising three distributed-constant lines. In one distributed-constant line, a standing wave is generated. Disposed adjacent thereto is another distributed-constant line to which the power of the standing wave is transferred. A signal input to the unbalanced-to-balanced converter is divided into two signals having phases 180 degrees apart and the same level.

37 citations


Patent
Jerzy Dabrowski1
04 Mar 1997
TL;DR: In this article, a multilayer dielectric balun with coupled striplines and via-holes is presented. But the operating frequency of the balun can be changed by changing values of the discrete components without changing the multillayer structure itself.
Abstract: Baluns according to the present invention use both distributed and discrete elements connected together in a multilayer dielectric structure. As distributed elements, coupled striplines are provided in the multilayer dielectric structure. The discrete components are placed on the surface of the multilayer structure and connected with the distributed elements through via-holes. The operating frequency of the balun can be changed by changing values of the discrete components without changing the multilayer structure itself.

34 citations


Patent
11 Mar 1997
TL;DR: In this article, a laminated balun transformer includes a dielectric sheet for which a lead electrode is provided at its surface, dielectrics for which ground electrodes are provided at their surfaces respectively.
Abstract: A laminated balun transformer includes a dielectric sheet for which a lead electrode is provided at its surface, dielectric sheets for which λ/4 striplines are provided at their surfaces respectively, and dielectric sheets for which ground electrodes are provided at their surfaces respectively. One pair of opposing striplines is provided with a dielectric sheet disposed therebetween so as to be electromagnetically coupled. The other pair of opposing striplines is provided with a dielectric sheet disposed therebetween so as to be electromagnetically coupled. An end of a stripline of one pair of striplines is electrically connected to an end of a stripline of the other pair of striplines through an external electrode.

29 citations


Journal ArticleDOI
TL;DR: In this article, the gate-line termination of a distributed amplifier topology is used as the noninverting output and the inherent phase inversion property of the metal-semiconductor field-effect transistor (MESFET) to provide the antiphase output from the drain-line.
Abstract: The principles of the distributed amplifier are applied to realize wide-band monolithic distributed baluns. The technique reported here is based on using the gate-line "termination" of a distributed amplifier topology as the noninverting output and the inherent phase inversion property of the metal-semiconductor field-effect transistor (MESFET) to provide the antiphase output from the drain-line. Closed-form expressions are derived for the two output voltage signals and their respective power gains. The theoretical performance of the balun is then examined as a function of the important MESFET parameters and other circuit parameters. Some practical design considerations are given followed by the measured results of two monolithic prototypes. The first is a basic two-section balun, while the second employs a four-section balun with a three-stage positive gain slope preamplifier to compensate for the increase in gate-line loss with frequency. Balun operation over 0.5-20 GHz and 0.5-12 GHz has been demonstrated for the two-section and four-section balun, respectively.

28 citations


Patent
Nobumi Harada1
30 Dec 1997
TL;DR: In this article, a multilayered balun signal transformer is proposed, in which not only loss can be suppressed but also phase difference or level difference between balanced signal terminals can also be suppressed and which become easy to design.
Abstract: A multilayered balun transformer in which not only loss can be suppressed but also phase difference or level difference between balanced signal terminals can be suppressed and which become easy to design. In the multilayered balun signal transformer, a coil 4 and a capacitor C1 are formed in a dielectric by a multilayered structure to thereby form a high-pass filter 6. A low-pass filter 9 is formed from another combination of a coil 7 and a capacitor C2. The high-pass filter 6 and the low-pass filter 9 are arranged lengthwise in the direction of multilayer so that the capacitors C1 and C2 are present on extensions of magnetic flux generated in the inside of the coils 4 and 7 respectively.

Proceedings ArticleDOI
08 Jun 1997
TL;DR: In this paper, the design and performance of microwave and MM-wave baluns using multilayer GaAs MMIC technology is presented for lower frequency bands at 30-40 GHz and 5-15 GHz.
Abstract: The design and performance of microwave and MM-wave baluns using multilayer GaAs MMIC technology is presented For MM-wave designs a compact overlaid coupler is employed For lower frequencies it is shown that novel spiral couplers can be used Results for baluns operating at 30-40 GHz and 5-15 GHz are presented

Patent
15 May 1997
TL;DR: In this article, an integrated antenna and phase shifter which has frequency-independent performance is presented, which comprises first and second conductive spirals which are identical to and aligned with each other and which are separated from each other by a thin sheet of dielectric material.
Abstract: The present invention provides an integrated antenna and phase shifter which has frequency-independent performance. In its preferred form, the antenna phase shifter of the present invention comprises first and second conductive spirals which are identical to and aligned with each other and which are separated from each other by a thin sheet of dielectric material. The first spiral has arms which are connected in a central region of the spiral to a first line of a balun or a balanced transmission line via electronic or optoelectronic switches. The second spiral has arms which are connected in the central region of the second spiral to a second line of the balun or balanced transmission line via electronic or optoelectronic switches. A switching circuit is used to turn them on and off. When any one of the RF switches is turned on, an RF link is established between the arm connected to the switch and the line of the balun connected to the switch. When one of the arms of one of the spirals is turned on, the associated arm in the adjacent spiral is RF coupled to the arm which is turned on due to the proximity effect. The RF switches are switched on and off by the switching circuit in such a manner that the spirals are in effect being electrically rotated. Frequency phase shifts in increments of 2π/N radians can be achieved, where N is the number of arms in each spiral.

Proceedings ArticleDOI
08 Jun 1997
TL;DR: In this paper, a low-loss monolithic Marchand balun was designed and fabricated using polyimide as the inter-metal dielectric, and the measured return loss was less than -10 dB from 5.5 GHz to 28 GHz.
Abstract: A low-loss monolithic Marchand balun has been designed and fabricated using polyimide as the inter-metal dielectric. The measured return loss is less than -10 dB from 5.5 GHz to 28 GHz. The balun loss is less than 0.7 dB over the 6 GHz to 21 GHz operating band. This is the lowest loss ever reported for such a balun. The excellent loss is the result of using a relatively thick polyimide layer (10 /spl mu/m) as the inter-metal dielectric. This balun has been applied to HBT and pHEMT amplifiers with second harmonic components suppressed >40 dB, even in compression, demonstrating very good push-pull operation.

Patent
Jean-Marc Mourant1
30 May 1997
TL;DR: In this article, a printed circuit balanced to unbalanced transformer is described, where the primary inductor has a first electrode adapted for coupling to an unbalanced transmission line and a second electrode electrically connected to the ground plane conductor.
Abstract: A printed circuit balanced to unbalanced (balun) transformer. The balun includes strip circuitry having first, second and third conductors. The first conductor provides a primary inductor of the transformer. The primary inductor has a first electrode adapted for coupling to an unbalanced transmission line and a second electrode electrically connected to the ground plane conductor. The second conductor provides a first secondary inductor of the transformer. The first secondary inductor is inductively coupled to a first portion of the primary inductor. A first electrode of the first secondary inductor is electrically connected to the ground plane conductor and a second electrode of the first primary inductor coupled to a first of a pair of output ports. The conductor provides a second secondary inductor of the transformer. The second secondary inductor is inductively coupled to a second portion of the primary inductor. A first electrode of the second secondary inductor is electrically connected to the ground plane conductor and a second electrode of the second secondary inductor is coupled to a second of the pair of output ports.

Patent
23 Jul 1997
TL;DR: In this paper, an electronically adjustable balanced-to-unbalanced converting method is described. But it is not shown how to use it in the real world, since it is computationally computationally expensive.
Abstract: Electronically adjustable baluns and electronically adjustable balanced-to-unbalanced converting methods are provided. The electronically adjustable baluns are responsive to an electronic tuning signal to electronically vary the frequency range thereof. The baluns may include an electronically variable transformer, capacitor or inductor or switched transformers, inductors or capacitors, or combinations of these elements.

Patent
31 Jul 1997
TL;DR: In this paper, the inline coaxial balun fed cornu flared horn antenna is formed by transitioning a coaxial transmission line to a parallel-plate transmission line with a Klopfenstein impedance profile and terminating with a scaled cornu spiral.
Abstract: The inline coaxial balun fed cornu flared horn antenna is formed by transitioning a coaxial transmission line to a parallel-plate transmission line with a Klopfenstein impedance profile and terminating with a flared horn antenna based on a scaled cornu spiral. The cornu spiral is a mathematical plane curve formed by parametrically plotting the scaled cosine Fresnel integral versus the scaled sine Fresnel integral. The antenna has the property that the curvature of the flare increases linearly in proportion to the arc length of the flare. The Klopfenstein impedance profile of the inline balun ensures a low voltage reflection across a wide bandwidth with a minimum transition length and together with the cornu flare satisfies the requirements for a wideband design. The design efficiently radiates and receives a high power pulse of ultrawideband electromagnetic waves over a preferred range of angles in space and transmits a field that is nearly the scaled temporal derivative of the input voltage signal and receives a voltage that is nearly the scaled replica of the incident field.

Journal ArticleDOI
TL;DR: In this paper, a simple dual-balun structure is proposed for a miniature monolithic microwave integrated circuit (MMIC) double doubly balanced mixer (DDBN) design, which achieves a high input IP3 of 24 dBm and a 1-dB compression input power of 13 dBm at 17dBm local oscillator (LO) drive.
Abstract: A simple dual-balun structure is proposed for a miniature monolithic microwave integrated circuit (MMIC) double doubly balanced mixer (DDBN) design. The dual balun is realized by using two out-of-phase power splitters in parallel, which are then applied in a DDBM mixer. The measured conversion loss of the mixer is less than 10 dB for a radio frequency (RF) bandwidth of 2-5.5 GHz and fixed intermediate frequency (IF) output frequency of 2 GHz. The mixer achieves a high input IP3 of 24 dBm and a 1-dB compression input power of 13 dBm at 17-dBm local oscillator (LO) drive. The chip area of the mixer is less than 1.0/spl times/1.4 mm/sup 2/, which is the smallest size ever reported for monolithic DDBM mixers.

Journal ArticleDOI
TL;DR: In this article, the authors present the design and performance of a very compact MMIC star mixer, composed of four diodes and two lumped dual baluns which are realized using two high/low-pass out-of-phase power splitters in parallel.
Abstract: The authors present the design and performance of a very compact MMIC star mixer. The mixer is composed of four diodes and two lumped dual baluns which are realised using two high/low-pass out-of-phase power splitters in parallel. The MMIC star mixer shows wide bandwidth, high PldB, high third order intercept (IP3) point and high port-to-port isolations both in the applications of up and down converter. The chip size of this star mixer is much smaller than those of the conventional mixers. To the best of the authors' knowledge, it is the smallest size ever reported for passive mixer operated at S-band.

Patent
18 Jul 1997
TL;DR: In this article, a lumped constant compensated high/pass balun (balance line to unbalance line transition) was proposed for microwave integrated circuits (MIC) and mononolithic microwave integrated circuit (MMIC) designs.
Abstract: The invention proposes a lumped constant compensated high/pass balun (balance line to unbalance line transition). The proposed circuit can be used in microwave integrated circuit(MIC) and mononolithic microwave integrated circuit(MMIC) designs. The basic operating 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 is compensated by the other filter set. The advantage of the proposed circuit is to replace the bulky and non-planar distributed balun or traditional transformer in low microwave frequency range.

Patent
15 May 1997
TL;DR: In this paper, a surface wave device consisting of first and second SPUDT (single phase unidirectional transducer) resonator filters (72, 74) is described.
Abstract: A surface wave device comprises first and second SPUDT (single phase unidirectional transducer) resonator filters (72, 74) each comprising first and second transducers, which are preferably RSPUDTs (resonant SPUDTs), the resonator filters being the same except that one transducer (R1M) of the second resonator filter is a mirror image of the corresponding transducer (R1) of the first resonator filter to provide a phase difference of 180°. The surface wave device serves as a balun by having an unbalanced signal connection (78) to the first transducers, and a balanced signal connection (84, 84') comprising signal connections to the second transducer of each of the first and second resonator filters. The resonator filters can be arranged side by side on a common piezoelectric substrate (76).

Patent
Tsutomu Endo1, Isamu Chiba1, M. Ohtsuka1, Yoshihiko Konishi1, Shuji Urasaki1 
03 Dec 1997
TL;DR: In this paper, a combination antenna device consisting of a helical antenna which supplies power to a coaxial line and a monopole antenna which is constituted of an outer conductor of the coaxial lines is presented.
Abstract: A combination antenna device wherein a helical antenna which is constituted of a helical element and supplies power to a coaxial line and a monopole antenna which is constituted of an outer conductor of the coaxial line are formed coaxially and therefore a gain in a horizontal plane can be made uniform and an occupation volume can be made small. At an upper end section of a coaxial line (11), a balun (16) connected to an inner conductor (12) of the coaxial line (11) is installed. One end of a helical element (17) constituted of a pair of wire conductors is connected to the balun (16), and the other end is swiveled around the coaxial line symmetrically about the center of the line in the direction opposite to the balun and is connected to an outer conductor (13) at a lower end section of the coaxial line. At the lower end section of the coaxial line, an inner conductor connection terminal (14) connected to the inner conductor of the coaxial line and an outer conductor connection terminal (15) connected to the outer conductor are installed.

Patent
09 Jul 1997
TL;DR: The use of two mixer cells (110, 110') in novel embodiments of quadrature and image reject mixers is disclosed in this article, where CPW to slot line power dividing baluns for use within and without such mixers are also disclosed.
Abstract: Mixer assemblies (100) including mixer cells (110, 110'), baluns (112), quadrature mixers and image reject mixers, etc. The mixer cell may contain CPW strip RF input and slot line strip LO input. LO signal return is provided through a flip-chip (160, 160') mounted to a mixer contact area (140, 140') and the CPW RF input is preferably coupled to the contact area (140, 140') through a distributed or flip-chip mounted capacitor (136, 136'). The use of two mixer cells (110, 110') in novel embodiments of quadrature and image reject mixers is disclosed. CPW to slot line power dividing baluns for use within and without such mixers are also disclosed.

Proceedings Article
01 Jan 1997
TL;DR: This paper describes a 2 V full CMOS 1 GHz upconversion mixer which has a single-ended output which avoids the use of any balun and the total power consumption in both the mixer and the output stage is only 22 mW.
Abstract: This paper describes a 2V full CMOS 1 GHz upconversion mixer. The circuit has a single-ended output which avoids the use of any balun. The total power consumption in both the mixer and the output stage is only 22mW. The signal to distortion ratio has been measured to be more than 30 dB. A thorough analysis of the harmonics caused by the nonlinearity of the mixer transistors is performed. The theory is confirmed by the measurements on the presented circuit. The chip has been processed in 0.4 ym CMOS technology.

Proceedings ArticleDOI
01 Aug 1997
TL;DR: In this paper, a new differential D-dot and B-dot monitor was developed for the Z vacuum section of an accelerator pulsed power supply, which measured voltage at the insulator stack and current at the stack and in the outer magnetically-insulated transmission lines.
Abstract: New differential D-dot and B-dot monitors were developed for the Z vacuum section of an accelerator pulsed power supply. The D-dots measure voltage at the insulator stack. The B-dots measure current at the stack and in the outer magnetically-insulated transmission lines. Each monitor has two outputs that allow common-mode noise to be cancelled to the first order. The differential D-dot has one signal and one noise channel; the differential B-dot has two signal channels with opposite polarities. Each of the two B-dot sensors in the differential B-dot monitor has four 3 mm diameter loops and is encased in copper to reduce flux penetration. For both types of probes, two 2.2 mm diameter coaxial cables connect the outputs to a Prodyn balun for common-mode-noise rejection. The cables provide reasonable bandwidth and generate acceptable levels of Compton drive in the bremsstrahlung field of the Z accelerator. A new cavity B-dot is being developed to measure the total Z current 4.3 cm from the axis of the z-pinch load. All of the sensors are calibrated with 2-4% accuracy. The monitor signals are reduced with Barth or Weinschel attenuators, recorded on Tektronix 0.5 ns/sample digitizing oscilloscopes, and software cable compensated and integrated.

Proceedings ArticleDOI
08 Jun 1997
TL;DR: In this paper, a lumped impedance matched type of Marchand balun in MMIC/MCM technology is described which is compact enough even for the low-GHz frequency range.
Abstract: A novel lumped impedance matched type of Marchand balun in MMIC/MCM technology is described which is compact enough even for the low-GHz frequency range. Broadband performance and balance of this component are sufficient for the use in many wireless applications.

Patent
07 May 1997
TL;DR: In this paper, a half-wave balun network balanced for at least current is provided by a conductor section having contiguous conductor portions 130 and 140, and an unbalanced port 120 is provided between one end of the conductor section and a ground plane 107.
Abstract: A half-wave balun network balanced for at least current is provided by a conductor section having contiguous conductor portions 130 and 140. A balanced port 110 is provided between ends of the conductor section. An unbalanced port 120 is provided between one end of the conductor section and a ground plane 107. A difference between impedances of the contiguous conductor portions 130 and 140 of the half-wave balun network provides for a selectable impedance ratio between the port impedances of the balanced and unbalanced ports 110 and 120. In one embodiment the number of different impedance conductor portions approaches infinity, thereby providing a tapered conductor section.

Journal ArticleDOI
TL;DR: In this paper, the authors derived analytical design equations for general integrated compensated baluns (Marchand baluns) based on the mode parameters of the associated coupled strip sections, and showed that a third-order Marchand balun is realizable with the use of two equal sections of coupled lines.
Abstract: Rigorous analytical design equations for general integrated compensated baluns (Marchand baluns) have been derived based on the mode parameters of the associated coupled strip sections. It is shown that a third-order balun is realizable with the use of two equal sections of coupled lines. Example components using planar as well as multilayer MMIC technology have been designed with the method presented here. Simulated results obtained by approximate TEM analysis as well as those generated with a 2.5D EM full-wave simulator show good broadband performance. © 1997 John Wiley & Sons, Inc. Microwave Opt Technol Lett 14, 75–81, 1997

Patent
21 Feb 1997
TL;DR: In this article, two Marchand baluns (56, 64) comprised mini-microstrip and mini-coplanar transmission lines formed on the chip substrate with two metal layers.
Abstract: Two baluns (56, 64), a quarter-wave transmission line (74) and a diode quad (72) are combined on a chip to form an MMIC mixer, and a pair of mixers are combined with 90 degree and 180 degree splitters to provide circuits with superior rejection of specific spurious signals as well as reduced RF and LO leakage. The two baluns (56, 64) comprise mini-microstrip and mini-coplanar transmission lines formed on the chip substrate with two metal layers. Together with a ground plane on the underside of the substrate, the lines are connected to form Marchand baluns (56, 64).

Patent
02 Jun 1997
TL;DR: In this paper, a directional antenna for telecomunication base station applications for home or business is provided, which includes a folded dipole, a passive reflector, a balun and selectively routed coaxial transmission line all enclosed in a plastic enclosure.
Abstract: A directional antenna for telecomunication base station applications for home or business is provided. A folded dipole, a passive reflector, a balun and selectively routed coaxial transmission line all enclosed in a plastic enclosure provide improved stability of operating parameters when subjected to significant installation variations. The use of a PVC or similar plastic enclosure results in increased bandwidth while permitting printed circuit techniques and similar electronic construction methods the necessary protection and structural integrity.