US Government As Represented by the Secretary of the Army

Watson P Czerwinski

Charles M DeSantis

John R Wills

Albert H Zannella

Michael W Begala

A low-profile survivable antenna suitable for military use is described. pite its small size, which might be one tenth of a wavelength, the antenna has reasonable transmission range for these applications. Very little operator attention is needed in use, since a special matching circuit within the antenna network enables effective impedance matching, over a 3:1 frequency range, without necessity of switching to different matching circuits over different frequency bands. By including resistive components along with other passive inductive or capacitive elements, the reactance of the single matching circuit is made to effectively compensate the antenna's impedance over the entire frequency range. The impedance of the circuit has a decreasing positive reactance which compensates for the decreasing negative reactance, with frequency, of the antenna. Although the transmission efficiency of the matched antenna network is somewhat diminished by resistive losses, it is still satisfactory, and band switching with this matching circuit is completely eliminated. By including a slender whip screwed into the top, the range can be doubled with no further changes. The matching techniques to be described are most easily realized in the HF through VHF range (1-200 MHz).

Lossy matching for broad bonding low profile small antennas

Small broadband antennas using lossy matching networks

A vehicular mounted loop antenna which operates as an NVIS radio communicon antenna over one range of frequencies and as a vertically polarized whip antenna over another range of frequencies corresponding to the frequency range of a radio communication set equipped with a conventional whip antenna. A coupling loop of variable area and a transmitting loop are positioned in a common vertical plane on a horizontally disposed base member, with the coupling loop positioned within the transmitting loop. A variable capacitor is in circuit with, and is an integral element of, the transmitter loop to provide resonance over the desired operating frequency range.

High frequency roll-bar loop antenna

Disclosed is a low profile wideband VHF antenna wherein impedance matching ver the required operating band is provided without the use of multiple circuit components, for tuning, switched into and out of the antenna by an assembly of switch contacts. The antenna is comprised of an end and preferably a bottom fed vertical radiating rod or monopole element whose upper end is terminated in a substantially flat circular top capacitance disc via a frequency sensitive inductance constructed of a ferrite core inductor whose .mu. characteristic varies approximately inversely with respect to frequency.

Wideband antenna with frequency dependent ferrite core inductor

What is disclosed is an antenna system for aircraft and one having particr utilization on a helicopter where there is a need, among other things, to eliminate insofar as possible rotor blade modulation of the signal radiated from on-board air-to-ground communication system in the 2 to 30 MHz band. The antenna comprises a current fed grounded loop-antenna having an electrical length which is relatively short with respect to the operating wavelength. The antenna conductor is mounted by means of insulators on the outside of the aircraft body, having one end connected to the transmitter while the other end is series connected to a lumped electrical inductance element whose opposite end is terminated in the metallic skin of the aircraft. The electrical inductance, moreover, is variable so as to resonate the antenna to the driving impedance of the transmitter.

High frequency aircraft wire antenna

A top termination for short monopoles is disclosed which reduces transmisn losses by placing the series inductor outside the top-capacitor-to-ground field while coupling the top capacitor to the monopole through said series inductor.

Growing community of inventors

Forked River, NJ, United States of America

Watson P Czerwinski