Thus, the total cost becomes appreciable especially as the number of antennas is increased. On the other hand, the expense of structural mounting, functional tests, and installation of antennas internally of the aircraft must be added to the initial cost of the antenna itself. It has been established that the drag for one external antenna on existing aircraft currently in service can amount to as much at 180 pounds. These factors are magnified substantially in the design of cost effective STOL aircraft and in heavily electronics-oriented military aircraft. The many electronic systems of airborne vehicles today require a multiplicity of antennas on the aircraft which present problems from several aspects, such as electromagnetic interference, cost, weight, available space, and drag. This invention relates to antennas generally, and to antennas as employed on aircraft in particular. The invention of claim 5 including a protective housing of dielectric material adapted to receive and enclose said antenna, and a mount carried by said housing to facilitate its connection to stationary structure of said aircraft. The antenna of claim 3 wherein said means for impedance matching is a capacitor formed by a diagonal extension of conductive material disposed on said one substrate surface and a conductive strip disposed on said opposite substrate surface in overlap relation with each other.Ħ. The antenna of claim 3 wherein said substrate has a thickness of about 0.03 inch, said first half-loop has a transverse dimension on the order of about 0.68 inch and a length of approximately 20.2 inches measured along its centerline and the overlap aforesaid in its length has an area of about 0.319 square inch to thereby tune said first half-loop to a frequency of about 108 to 118 megahertz, and said second half-loop has a transverse dimension on the order of about 0.30 inch and a length of approximately 6.6 inches measured along its centerline and the overlap aforesaid in its length has an area of about 0.0102 square inch to thereby tune said second half-loop to a frequency of about 327 to 335 megahertz.ĥ.
The antenna of claim 2 including a substrate of dielectric material and wherein said first and second half-loops and said shunt feed line are disposed on one surface thereof, said conductors are each disposed on the opposite surface thereof, and each said capacitor is formed by an overlap in the length of each half-loop and each said conductor.Ĥ. The antenna of claim 1 wherein one outside edge of said second half-loop is generally tangent to said centerline and said shunt feed line is located between the other outside edge of said second half-loop and the adjacent first half loop end portion.ģ. A combination glideslope/localizer antenna for aircraft comprising:Ģ.
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