The short backfire (SBF) antenna consisting of a large reflector illuminated by a dipole feed and smaller disk reflector produces a gain of 15 dB above isotropic. As an array element it has been efficiently adapted for various configurations of high-gain antennas producing gains of up to 25 dB, with a single SBF element capable of replacing four to six elements of a conventional multidipole array. Farfield patterns and directivity measurements are presented for a single element and for a twin element mounted on a common reflector. Optimized dimensions for both cases are discussed for possible application to more complex types of antennas.

Short-backfire (SBF) antennas can be simply converted into highly directive and efficient array elements. Each SBF element is the equivalent of four to six dipole elements of conventional multielement arrays. Models of two-, four-, and eight-element SBF arrays have yielded gains of 17, 19, and 22 dB, respectively. Radiation patterns are presented, including the sum and difference patterns in the two major planes (E and H), as well as those for diagonal cuts at plus or minus 45 degrees. All physical dimensions are given in wavelengths so that each model can be easily scaled for any desired frequency. (Author).

Four-element short-backfire (SBF) arrays have been shown to yield maximum gains of approximately 20 dB. The influence of parameter variations on the array patterns has been experimentally determined. Specific parameter values required to yield certain pattern characteristics--for example, highest gain, lowest sidelobe level, equal half-power beamwidth, or equal beam shapes in both the E and H planes--have been established. Tables of the normalized design parameters are given for construction purposes. All array dimensions are indicated in wavelengths so that each model can easily be scaled for any desired frequency range. (Author).

Eight short backfire (SBF) elements aligned on a common planar reflector form a highly efficient fan-beam array capable of yielding a maximum gain of approximately 24 dB. The influence of parameter variations on the array patterns and directivity was experimentally determined by varying the frequency. Normalized design parameters for highest efficiency and for circular polarization capability are tabulated. All array dimensions are given in wavelengths so that each application can easily be scaled for any desired frequency.

A four-element short-backfire array was designed, fabricated, and experimentally tested for use as a receiving antenna of low level atmospheric noise at 920 MHz. A complete set of design dimensions is presented as well as the resultant radiation patterns and frequency curves of sidelobe levels, half-power beamwidths, and input impedance. The effects of variations on the size and shape of the main reflector are discussed, especially when efficient operation with low sidelobes or high gain is of prime importance. Supporting data and tables of optimum design dimension are also provided for future VHF or UHF antenna applications in the gain range of 17 to 20 dB.

Sixteen-element short-backfire arrays have been shown to yield maximum gains of approximately 25 dB. The influence of parameter variations on the array patterns and directivity has been experimentally determined by varying the frequency. A table of the normalized design parameters for an area efficiency of approximately 90 percent is given for construction purposes. All array dimensions are indicated in wavelengths so that each application can easily be scaled for any desired frequency range.