Showing papers on "Balun published in 1970"

Double balanced microwave mixer using balanced microstrip baluns

Abstract: A microwave mixer using a double balanced diode bridge arrangement, provided with a signal input, a local oscillator input and an output. Microstrip baluns, having their ground plane metallic strip tapered, are connected between the inputs and the bridge. The diode bridge is assembled in a package wherein all the connections are of substantially identical lengths, and is placed in a substrate which is suspended in air within a housing.

A Wide-Band Parallel-Connected Balun

Abstract: It is pointed out that parallel-connected baluns (4:1 impedance transformation) have approximately four times the operating bandwidth of series-connected baluns (1:1 impedance transformation). The simple theory of uncompensated resonant baluns is discussed, and design curves are presented which may be used to design any balun of this type. Experimental results are given on one type of parallel-connected balun showing it capable of a 25:1 operating bandwidth as predicted by theory. Operating over this bandwidth, the balun is only /spl lambda/ / 25 in length at the lower band-edge frequency. Because of its 4:1 impedance transformation, the balun should be very useful in the feeding of frequency-independent antennas with high impedance, such as the conical spiral.

Orthogonal dipole antennas

Abstract: A drooping dipole antenna having a center combination supporting mast and indicator balun structure with the drooping dipoles electrically close to the ground and part of the guy support system for the antenna effective primarily in the skywave mode of operation, but also producing a useful vertically polarized surface wave component with the droop of the dipole elements. Further, with two of these antennas colocated in an orthongonal configuration and the two antennas substantially at right angles sufficient mutual isolation is advantageously attained that the two input terminals are connectable simultaneously to two transmitters, two receivers, or one transmitter and one receiver.

Broadband power amplifier with multiple stages connected by balun transformers

Abstract: Broadband power amplifier including a single ended stage coupled to a plurality of stages by use of balun transformers. Broadband operation is achieved by use of balun transformer having interwinding capacitance which forms a shunt element, and high power is provided by use of a plurality of stages contributing to the load. A first single ended stage may be coupled by a one-toone balun to a pair of push-pull stages, which in turn may be coupled through balun transformer to two pair of push-pull transistor stages. Alternately the single ended stage can be connected by two balun transformers to two pair of push-pull stages, or may be connected by three or more balun transformers to a like number of single ended stages. The outputs can be combined by use of a plurality of balun transformers coupled in series and each providing impedance step-up or by use of transformers, to thereby provide the desired output impedance of the amplifier.

Wide band balun

Abstract: A wide band balun for connecting an unbalanced coaxial input line to a balanced load. The input line is separated into a first and a second portion by a gap in its outer conductor. The balun achieves wide band operation by the use of two short circuited stubs in shunt with respect to the gap and an open circuited stub in series with respect to the gap.

Input Impedance Analysis of 1:1 Balun

Abstract: The 1:1 balun constructed of a bifilar delay line and an inverse 1:1 transformer is analyzed for its input characteristics. As a main result of the analyses, the following results were obtained about the balun in this paper. 1) Resonance occurs when the line length is equal to n (any positive integer) times half of a wavelength of the unbalanced transmission mode. 2) The lower cutoff frequency is determined by electromagnetic coupling coefficient "k/sub m/" when L/sub sigma/ and /spl iota/ are constant. 3) The upper cutoff frequency is also given by a combination of k/sub m/ and k/sub e/, etc. 4) Shortening of the distance between the balun and the ground makes the resonant frequency lower when the balun has a magnetic core or when the electrostatic coupling coefficient "k/sub e/" becomes smaller and k/sub m/ is kept constant. /spl omega//sub OI/ becomes lower. 5) In order to realize a wide-band balun, /spl beta//sub b/ / /spl beta//sub u/ shouId be larger and and /spl beta//sub b/ / /spl omega/ should be kept constant.