US2478313A - Antenna construction - Google Patents

Description

Aug 9, 1949- H. o. PETERSON ANTENNA CONSTRUCTION Filed July l19, 1945 z 2 a z INVENTOR.

m www D@ awo. ww, 0^ mw Patented Aug. 9, 1949 ANTENNA CONSTRUCTION Harold O. Peterson, Riverhead, N. Y., assgnor to Radio Corporation of America, a corporation of Delaware Application July 19, 1945, Serial No. 605,982

3fGl'aims. (Cl.V Z50-m33)` The present invention relates to short wave antennas.

An object of the present invention is to increase the reliability of operation of ultra short wave antennas and associated matching sections.

Another object of the present invention is to decrease the physical size of the matching stubs associated with ultra short wave antennas.

A further object of the present invention is the provision of an ultra short wave antenna which is not subject to losses in efficiency due to moisture, rain, snow, etc., entering the transformation and matching stub sections associated with the antenna.

The foregoing objects and others which may appear from the following detailed description are obtained by providing, in a balanced antenna fed from an unbalanced transmission line, solid dielectric insulating material in the bazooka or line balance converter coupling the transmission line to the balanced antenna.

The present invention will be more fully understood by referring to the following detailed description which is accompanied by a drawing wherein reference numerals Il] and identify a pair of opposed arms of a half wave dipole antenna. To the adjacent ends of arms lll and are connected the conductors of a coaxial transmission line TL. Thus inner conductor 20 is connected to the inner end of arm and outer sheath 2| is connected to the inner end of arm In order to electrically free the end of sheath 2| from ground, the sheath is surrounded by an outer shell 22 having an electrical length equal to one quarter of the operating wavelength and connected to sheath 2| at the end remote from the free end of sheath 2|. Thus, energy unbalanced with respect to ground ilowing along the interior ci transmission line energizes rods l0, in equal and opposite instantaneous polarities. In order to prevent water from rainstorms, rough seas, etc. from iilling up the shell 22 and thus impairing its operation, the shell is lled with a solid dielectric material 24. The dielectric material may be methylmethacrylate, commonly known as Lucite, polystyrene or polyethylene. The solid dielectric material not only maintains the electrical efficiency constant at all times but also acts as a supporting means for maintaining the concentric relationship between outer sheath 2| and shell 22. Also since the dielectric material 24 extends over the adjacent ends oi dipole arms l0, it acts as a support to maintain them in concentric endto-end relationship whereby the radiation pattern of the antenna is maintained constant. Since the dielectric constant of any of the solid dielectrics mentioned above is considerably higher than that of the dielectric constant of air, the mechanical length of shell portion 22 is shorter than the electrical length, thereby making the structure more compact. It is therefore less subject to mechanical damage.

While I have illustrated a particular embodiment of the p-resent invention, it should be clearly understood that it is not limited thereto since many modifications may be made in the several elements employed and in their arrangement and it is therefore contemplated by the appended claims to cover any such modifications as fall within the spirit and scope of the invention.

What is claimed is:

l. A short wave antenna including a pair of elongated conductors in end-to-end relationship, a Coaxial transmission line having an inner conductor and an outer sheath conductor, an outer shell having an electrical length equal to one quarter of the operating wavelength of said antenna surrounding the end of said line and connected to said sheath at its end remote from the end of the line, each of the adjacent ends of said conductors being connected to one of the conductors of said transmission line and a low loss solid dielectric material filling the space between the conductors of said line and the space between said shell and said sheath, said solid dielectric material extending outwardly of the end of said shell and surrounding the adjacent ends of said elongated conductor whereby they are maintained in position.

2. A short wave antenna including a pair of elongated conductors in end-to-end relationship, a coaxial transmission line having an inner conductor and an outer sheath conductor, an outer shell having an electrical length equal to one quarter of the operating wavelength of said antenna surrounding the end oi said line and connected to said sheath at its end remote from the end of the line, each of the adjacent ends of said conductors being connected to one of the conductors of said transmission line and a low loss solid dielectric material lling the space between said shell and said sheath, said solid dielectric material extending outwardly of the end of said shell and surrounding the adjacent ends of said elongated conductor whereby they are maintained in position.

3. A short wave antenna including a pair of elongated conductors in end-to-end relationship, a coaxial transmission line having an inner conductor and an outer conductor, an outer conductive shell coterminous with said transmission line having an electrical length equal to one quarter of the operating wave-length of said antenna and surrounding the end of said line and connected to said outer conductor at the end of said shell remote from the end of said line, each of the adjacent ends of said elongated conductors being connected to one of the conductors of said transmission line, and a low loss solid dielectric material filling the space between the conductors of said line and the space between the outer conductor of said line and said shell and extending outwardly from the end of said shell and surrounding the adjacent ends of said elongated conductors to maintain the relative spacial position of said inner and outer conductors, said shell and said elongated conductors and simultaneously to close the end of said transmission line to the external atmosphere.

HAROLD O. PETERSON.

4 REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,854,255 Green Apr. 19, 1932 2,111,743 Blumlein Mar. 22, 1938 2,193,017 Bassett Mar. 12, 1940 2,213,276 Gossel Sept. 3, 1940 2,234,068 Wiseman Mar. 4, 1941 2,249,963 Lindenblad July 22, 1941 2,304,210 Scott Dec. 8, 1942 2,322,971 Roosenstein June 29, 1943 2,337,556 Hosking Dec. 28, 1943 2,348,919 Milton May 16, 1944 2,350,916 Morrison June 6, 1944 2,407,057 Carter Sept. 3, 1946 2,411,034 Gluyas Nov. 12, 1946 2,412,867 Briggs Dec. 17, 1946

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