Search Images Maps Play YouTube News Gmail Drive More »
Sign in
Screen reader users: click this link for accessible mode. Accessible mode has the same essential features but works better with your reader.

Patents

  1. Advanced Patent Search
Publication numberUS2617934 A
Publication typeGrant
Publication dateNov 11, 1952
Filing dateMay 2, 1945
Priority dateMay 2, 1945
Publication numberUS 2617934 A, US 2617934A, US-A-2617934, US2617934 A, US2617934A
InventorsMcmillan Edward B, Redheffer Raymond M
Original AssigneeMcmillan Edward B, Redheffer Raymond M
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Antenna housing
US 2617934 A
Abstract  available in
Images(1)
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

Nov. 11, 1952 E. B. MOMILLAN ETAL ANTENNA HOUSING Filed May 2, 1945 FIG.|

PIC-3.2

N R mum mu m VWW m Mn BM D m 0 M ww RB ATTORNEY Patented Nov. 11, 1952 ANTENNA HOUSING Edward B. McMillan, Greenwood, and Raymond M. Redheffer, Cambridge, Mass., assignors, by mesne assignments, to the United States of America as represented by the Secretary of War Application May 2, 1945, Serial No. 591,585

1 Claim. 1

This invention relates in general to antenna housings and more particularly to antenna housings having laminated construction.

I In radio communication systems employing carrier frequencies in the ultra high frequency and microwave hands, it is practicabl to use antenna housings because of the reduced size of the antenna apparatus. Such housing plays an important part in antenna assemblies because it protects delicate antenna assemblies against inclement weather, blows from solid objects, and strong wind pressures encountered in airborne installations.

A housing, consisting of on layer of plywood, plastic, or other material which is transparent to radio energy, will aflord the advantages mentioned above. However, the electromagnetic waves radiated from the antenna within the housing will be reflected at least in part from any surface which separates media of different dielectric constants. This means that, in general, there will be reflection from the housing, since any material of which it may be made will have a. dielectric constant appreciably different from that of the surrounding air. Such reflections reduce the amount of electromagnetic energy eventually transmitted through the wall; moreover, these reflections distort the predetermined energy distribution pattern of the antenna.

In many high frequency radio communication systems, it is desired to enclose in a housing a highly directional rotatable antenna. The magnitude and phase of the energy reflected by the housing wall may vary with the position of the antenna because of non-uniform transparency of the housing. A portion of the reflected energy may be absorbed by the antenna and communicated back to the transmitter so that a nonuniform impedance is presented to the radio frequency generator. This may result in a condition of frequency instability.

Therefore, it is one object of the present invention to provide an antenna housing which minimizes undesirable reflections.

Another object is to provide an antenna housing which will have desired transmission characteristics and will also protect antenna assemblies from wind, weather, and accidental blows, and which is lightweight, yet strong.

These and further objects of this invention will be evident to those skilled in the art upon reference to the following specification, claim, and drawings, in which:

Fig. 1 shows several possible antenna installations to which a housing of the type disclosed herein is especially adaptable; and

Fig. 2 shows a cross-sectional view of thewa-ll construction of such a housing.

Briefly, the invention consists of laminating two dissimilar materials in a sandwich fashion,

yielding a three-ply sheet with a low density, low dielectric core surrounded by thin skins of high mechanical strength. The materials comshown. An airplane 5, carrying an ultra high frequency radio communication system, may have the antenna for the system mounted in th nose of the plane, in which case the housing 6 will bea continuation of the outer skin of the-plane. An antenna may also be mounted in a turret-like housing I on the upper side of the plane, or

alternatively, as at 8, on the under side. These turrets may be retractable if it is so desired. It is to be emphasized that these three alternatives do not exhaust the possible uses of antenna housings but are presented only as examples.

In Fig. 2, a section of housing wall is shown.

It consists of two skins I 0 and II of the same thickness d and di-electric constants a, and a core l2 having a dielectric constant B, and a thickness at.

Double wall housings are well known in the art, having been developed to reduce the objectionable reflections described hereinabove. These double wall housings generally consist of two skins separated by spacers placed at intervals around the housing. A major difliculty with this type of structure is the non-uniform wall thickness, this variable wall thickness afiecting the transmission of extremely high frequencies or microwaves through a housing. The wall tolerance is a function of wavelength; the shorter the wavelength, the closer the tolerance. Also, the wall thickness tolerance is a function of skin thickness, tolerance and skin thickness varying inversely. It can be seen that the application of external forces to such a housing may flex the outer skin, altering th skin spacing with adverse effect. Alternatively, if the skin is made thick enough to be rigid, the tolerances allowable are too great to allow ease of manufacture.

The sandwich type housing has the advantages of the simple double wal1 type without its disadvantages. Th core can be manufactured to accurate thicknesses, and very thin, mechanically strong skins can be bonded thereto. The use of a sandwich composition for mechanical strength is not novel. However, heretofore such construction has not been made according to optiwhere mum electrical properties, X=thickness of said core A principal factor in minimizing reflections is \=free space wavelength of electromagnetic the core thickness. It has been found, that for energy a normally incident electromagnetic wave, it is N=any integer possible to obtain the optimum core thickness in a=dielectric constant of said skins terms of the other variables of the sandwich, fi=dielectric constant of said core, and using the expression: d=thickness of said skins wher i e 20 whereby energy reflections from saidv skins and Xzoptimum thickness of core I2 said core will combine in a subtractive manner \=freespace wavelength of electromagnetic when radiant energy i p opa ted in a direction energy normal to said housing wall, thus to provide sat- Nlany integer isfactory transmission characteristics through ;-=dielectr-1c constant of skins l0 and l l 25 Said housing- :dielectric constant of core I2 I EDWARD B. McMILLAN. d=thickness of skins l0 and H v RAYMOND M. REDHEFFER.

- A'housing constructed according to this rela- REFERENCES CITED tion will exhibit electrical characteristics marked- 1y improved over previous types of housings, and U0 The following references are of record in, the

advantages of mechanical strength and ease of me of thls patent:

manufacture as elaborated hereinbefore. It will, UNITED STATES PATENTS of. course, be understood that slight departures Number Name Date from optimum values may be tolerated without 1 557 049 Hammond Oct 13 1925 substantial loss of the values of the invention. 2202:380 Hellman i, 1940 fwhat 1s clalmed 2,223,224 Newhouse Nov. 26 1940 7 An antenna housing having a wall construc- 2 304 540 Cassen Dec 8 1942 tion c'omprising two skins of predetermined thick-'- 2376653 Boyer 1945 ness spaced apart by a core also of predeter- A0 2405992 Bruce mined thickness, said skins being substantially 2407911 Tonks "s compOSition and thickness, said Skins 24 and said cor being of material transparent to 2415352 Iams b radiant electromagnetic energy, said wall being 221171052 Bemofff M 1947- proportioned substantially according to the following relationship: 45

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US1557049 *May 10, 1918Oct 13, 1925Hammond Jr John HaysElectrical antenna
US2202380 *Nov 11, 1937May 28, 1940Telefunken GmbhConfined or space resonance antenna
US2223224 *Jun 24, 1939Nov 26, 1940Bell Telephone Labor IncRadio speed and drift indicator
US2304540 *May 2, 1940Dec 8, 1942Westinghouse Electric & Mfg CoGenerating apparatus
US2376653 *Mar 31, 1942May 22, 1945Gen ElectricLaminated structure
US2405992 *Jan 19, 1944Aug 20, 1946Bell Telephone Labor IncDirective antenna system
US2407911 *Apr 16, 1942Sep 17, 1946Gen ElectricWave propagation
US2413085 *Jan 29, 1945Dec 24, 1946Philco CorpAntenna system
US2415352 *Apr 22, 1944Feb 4, 1947Rca CorpLens for radio-frequency waves
US2417052 *Feb 25, 1942Mar 11, 1947Submarine Signal CoHigh-frequency spark circuit
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2821706 *Sep 9, 1954Jan 28, 1958Glenn L Martin CoAntenna mounting for a guided missile
US2929581 *Nov 26, 1954Mar 22, 1960Goodyear Aircraft CorpAirship-enclosed radar unit
US2955776 *Oct 24, 1958Oct 11, 1960Boeing CoAircraft with integral antenna
US2956281 *Sep 8, 1954Oct 11, 1960Edward B McmillanDielectric walls for transmission of electromagnetic radiation
US2962717 *May 13, 1957Nov 29, 1960Boeing CoMicrowave apparatus housing and method of constructing the same
US3002190 *Apr 15, 1955Sep 26, 1961Zenith Plastics CompanyMultiple sandwich broad band radome
US3045236 *Sep 28, 1954Jul 17, 1962Lockheed Aircraft CorpRotatable radomes for aircraft
US3135511 *Feb 27, 1961Jun 2, 1964Hayes CorpTowed target
US3175220 *Apr 13, 1955Mar 23, 1965Hughes Aircraft CoStreamlined radome with ridged walls to compensate for boresight error
US3299355 *Mar 11, 1964Jan 17, 1967Television Audit CorpRadio and television audience survey system
US5575438 *May 9, 1994Nov 19, 1996United Technologies CorporationUnmanned VTOL ground surveillance vehicle
US8094062 *Dec 18, 2006Jan 10, 2012Telefonaktiebolaget L M Ericsson (Publ)Fore/aft looking airborne radar
US20100090881 *Dec 18, 2006Apr 15, 2010Hoeoek AndersFore/aft looking airborne radar
EP0248958A1 *Jun 12, 1986Dec 16, 1987Varian Associates, Inc.Triple pane waveguide window
Classifications
U.S. Classification343/907, 343/872, 343/705, 343/755
International ClassificationH01Q1/42
Cooperative ClassificationH01Q1/422
European ClassificationH01Q1/42C