Showing papers on "Balun published in 1987"

Patch radiator element with microstrip balian circuit providing double-tuned impedance matching

Abstract: A low-profile patch radiator for use in an array antenna has a multilayer structure which includes a double-tuned impedance matching network and balun and a coaxial feed for linear polarization of the radiated waves. A second embodiment further includes a second double-tuned impedance matching network and balun and a second coaxial feed for dual polarization operation. The matching networks/baluns, which comprise microstrip circuits on Duroid substrates, increase the frequency bandwidth of the patch radiator.

Microstrip fed printed dipole with an integral balun and 180 degree phase shift bit

Abstract: An improved element for use in an electrically steered antenna array is disclosed comprising a dipole, an integral balun and a 180° phase shift bit. The arrangement utilizes printed circuit techniques throughout using an unbalanced microstrip for connection to electrical circuitry, a balun for transitioning from unbalanced microstrip to a balanced dipole antenna and includes a low loss 180° phase shift bit formed by the use of a branched feed network including two diodes whose conductive states determine the sense of antenna excitation, and produce the equivalent of a 180° phase shift bit.

Microstrip balun-antenna

Abstract: An balun/antenna apparatus is provided which is capable of being fabricated on a printed circuit board substrate by automated equipment. The balun-antenna includes a microstrip groundplane conductor which is split into two balanced ground arms at one end. The split groundplane conductor operates as both a balun and as a radiating conductor. A unique microstrip excitation structure is situated above the split ground elements on the opposed surface of the substrate to excite the antenna with radio frequency energy.

VHF-UHF mixer having a balun

Abstract: A VHF-UHF mixer, which has a balun (14) having a ferrite core (141), a pair of R-C parallel connection circuits (15a) and (15b) connected to output ends of the balun (14), a series connection of two mixing diodes (16a) and (16b) connected across output ends of the R-C parallel connection circuits, and a diplexer (17) consisting of a high pass filter and a low pass filter and connected by its input terminal to center connection point (18) of said series connection of the two mixing diodes, further has a pair of impedance circuits (19a,19b), each being grounded by one ends thereof, consisting of L-C-L series connection circuit, and connected to either input end or output end of the R-C parallel connection circuit.

Nonreciprocity and scan blindness in phased arrays using balanced-fed radiators

Abstract: It is shown that scanning an array of balanced wire or patch type radiators in their E -plane can destroy the radiators' dual probe symmetry. This loss of symmetry can cause the radiator's unit cell "scattering matrix" to be nonreciprocal, where in this scattering matrix each of the radiator's dual probes is now considered as a separate input port. This breaking of radiator symmetry can result in scan blindness when the radiator is fed by a reactive power divider balun. This effect is illustrated by a numerical example using balanced-fed patch radiators.

Distortion generating circuit

Abstract: Microwave circuitry is disclosed for a distortion generating circuit. Input and output baluns are disposed on the tap surface of a substrate while secondary and primary conductors are respectively juxtaposed under these baluns. Four diodes connected in a star configuration are coupled between the primary and secondary conductors. The carrier signal may be fed into the input balun which is coupled to the secondary conductors and across the diode star configuration, generating intermodulation signals while suppressing the carrier signals. The intermodulation signal is coupled from the primary conductors to the output balun where it may be fed to a microwave amplifier to cancel intermodulation by-products thereof. A DC signal may be impressed across the diode star configuration to adjust the amplitude of the intermodulation signal generated by the diodes.

Double balanced type frequency converter

Abstract: PURPOSE:To increase the highest frequency limit and to widen the frequency characteristic by using a balun so as to convert the unbalanced mode into the balanced mode. CONSTITUTION:Rectangular main lines 4a, 5a are formed to the rear side of a dielectric board 11, an input terminal 2 for a local oscillation signal LO connected with a small capacitance 8a is provided to the outer ridge of the main line 4a and an input terminal 1 of a radio frequency signal RF is provided to the outer ridge of the main line 5a. Strip sub lines 4b, 4c and 5b, 5c in opposition to the main lines 4a, 5a respectively are formed vertically to the surface of the board 11. Then the inner ridge of the sub lines 4a, 4b is connected via a throughhole 4d. The lines 5b, 5a are connected similarly as above. Further, a strap line 7 connects a couple of sub lines 4b, 4c. Thus, the signal LO is converted from the unbalanced mode into the balanced mode by the balun 4 to excite diodes 6a-6d with the same amplitude but opposite phase. Then the radio frequency signal RF is converted in the reverse mode to above by the balun 5, and inputted to the diodes 6a-6d with the same amplitude but opposite phase and the result is mixed with the local oscillation signal LO. The signal IF is sent from an output terminal 3 via a line 7. In this case, capacitors 8a-8c are selected to minimize the conversion loss. Thus, the conversion efficiency is improved and the inter modulation ratio is decreased.

Multi-functional floating transistor circuit

Abstract: A transistor circuit is provided with a symmetrical floating configuration for attaining multi-­function operation of a transistor (20) having symmetrical source and drain characteristics, preferably a GaAs MESFET. The circuit includes a balun (30) which may be configured as a transformer, a differential amplifier, or a magic-tee waveguide depending on the frequency of signals to be processed by the circuit. Balanced terminals of the balun may be directly or capacitively coupled to source and drain terminals of the transistor (20). Tuning circuits (70, 72) are employed for applying signals having different frequencies to the transistor and for extracting intermodulation products generated by the transistor in response to the signals at the different frequencies. With the direct connection between the balun and the transistor, alternating voltages (via E, F, G) may be impressed between the terminals of the transistor to alternate source and drain regions of the transistor. Functions of amplification, modulation, bipolar attenuation, four-­quadrant multiplication and correlation, power frequency tripling, and mixing are obtainable. The transistor may be replaced with a pair of transistors connected in series or in antiparallel connection.

Single Sided Slotline Microstrip Transition

Abstract: A single-sided microstrip-slotline transition is described. It uses a balun in the form of an open ring consisting of two microstrip lines connected to a slotline through a pair of coupled microstrip. The transition transforms an unbalanced microstrip to a balanced slotline and also serves as an impedance matching network between the two lines. An experimental and theoretical study is presented. Different parameters of the transition are optimised to obtain best results

Double balanced frequency multiplier

Abstract: PURPOSE:To increase the maximum frequency limit and to widen the frequency characteristic by flowing a current of the unbalanced mode at the outer side of a balun and a current of the balanced mode at the inner side. CONSTITUTION:Main lines 4a, 5a are formed on a dielectric board 11 by a metallic conductor layer and an input terminal 1 and an output terminal 2 are provided at the center of the outer ridge. The input/output terminals 1, 2 are connected to ground potential. A couple of sub lines 4b, 4c and 5b, 5c are formed vertically in opposite to the main lines 4a, 5a. Then a through hole 4d is provided to the inner side of the main line 4a via the board 11 from the inner edge of the sub line 4b, the sub line 4b and the main line 4a are connected and the connection above is similar in the connection between the sub line 5b and the main line 5a. A bridge circuit comprising diodes 6a-6d is connected between the baluns 4, 5 constituted in this way. Thus, a current of the unbalanced mode flows between each outer edge of the baluns 4, 5 and the ground conductor and electric fields of the same amplitude but opposite phase are produced at each inner side. Thus, the broad band characteristic is obtained and the multiplier is used even at a high frequency region.

Design and Performance of Rugged High Performance Broadband Diode Mixers for Airborne Applications

Abstract: The analysis of the single diode quad ring mixer incorporating broadside coupled suspended microstrip baluns and a 4-wire balanced line is presented. Design trade-offs and guidelines are presented. Practical results of multi octave, highly rugged, high performance up/down frequency converters for airborne applications are presented.

Floating fet amplifier including balun

Abstract: A transistor circuit is provided with a symmetrical floating configuration for attaining multi-­function operation of a transistor (20) having symmetrical source and drain characteristics, preferably a GaAs MESFET. The circuit includes a balun (30) which may be configured as a transformer, a differential amplifier, or a magic-tee waveguide depending on the frequency of signals to be processed by the circuit. Balanced terminals of the balun may be directly or capacitively coupled to source and drain terminals of the transistor (20). Tuning circuits (70, 72) are employed for applying signals having different frequencies to the transistor and for extracting intermodulation products generated by the transistor in response to the signals at the different frequencies. With the direct connection between the balun and the transistor, alternating voltages (via E, F, G) may be impressed between the terminals of the transistor to alternate source and drain regions of the transistor. Functions of amplification, modulation, bipolar attenuation, four-­quadrant multiplication and correlation, power frequency tripling, and mixing are obtainable. The transistor may be replaced with a pair of transistors connected in series or in antiparallel connection.