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Publication numberUS3882506 A
Publication typeGrant
Publication dateMay 6, 1975
Filing dateFeb 20, 1974
Priority dateFeb 20, 1974
Publication numberUS 3882506 A, US 3882506A, US-A-3882506, US3882506 A, US3882506A
InventorsNorio Ikeda, Yujiro Katsube, Kenzo Mori
Original AssigneeTaiyo Musen Co Ltd
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Antenna for direction finders with mast isolation
US 3882506 A
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Description  (OCR text may contain errors)

United States Patent 1191 Mori et al.

[ May6,1975

ANTENNA FOR DIRECTION FINDERS WITH MAST ISOLATION Inventors: Kenzo Mori; Yujiro Katsube, both of Tokyo; Norio lkeda, Ichikawa, all of .l apan Assignee: Taiyo Musen Co. Ltd., Tokyo, Japan Filed: Feb. 20, 1974 Appl. No 443,949

US. Cl. 343/728; 343/842; 343/885 1111. c1. H0lq 21/00 Field of Search 343/113 R, 124,728,842,

References Cited UNITED STATES PATENTS 2,408,034 9/1946 Bcllare 343/728 Primary Examiner-Eli Lieberman Attorney, Agent, or Firm-A. W. Breiner [57] ABSTRACT An antenna device for direction finders wherein a sense determining vertical antenna is provided at the center of two loop antennas arranged so as to rectangularly intersect with each other and a primary winding in a transformer for taking a sense determining output out of its secondary side is connected on both sides respectively with the lower central point of said loop antenna or its shield and the lower end of the vertical antenna without earthing said loop antenna or its shield.

1 Claim, 5 Drawing Figures ANTENNA FOR DIRECTION FINDERS WITH MAST ISOLATION This invention relates to antenna devices for direction finders.

As a sense determining vertical antenna for direction finders, there has been already utilized a loop antenna itself having a directivity or a vertical antenna erected at the center of a loop antenna, connected with a feeder line and having had it shield earthed.

However, in case such antenna device is fitted to the upper end of a supporting pole, when the supporting pole or the feeder line perfectly or substantially tuned with incident waves, a voltage induced by the tuned current will be generated in the sensing antenna and the sense determination will be obstructed. If the sensing antenna is set in a position separated from the upper end of the supporting pole, needless to say, such difficulty will not be produced but it will be impossible to fit the antenna.

An object of the present invention is to provide an antenna device wherein a sense determining vertical antenna is set in a position substantially separate from the upper end of a supporting pole by utilizing loop antennas to prevent the above described troubles.

In the drawings:

FIG. 1 is a side view ofa device according to the present invention;

FIG. 2 is a sectioned view on line A-A in FIG. 1;

FIG. 3 is a view showing a wiring in an embodiment of the device according to the present invention;

FIG. 4 is a view showing a wiring in another embodiment;

FIG. Sis a voltage distribution diagram for explaining the operation of the present invention.

In FIGS. I to 3, two loop antennas 3 and 4 fitted respectively with tubular shields 1 and 2 are arranged so as to rectangularly intersect with each other and a sense determining vertical antenna 5 is provided at their center. A hollow antenna base 7 formed of an insulator is provided at the upper end of a supporting pole 6 to fit the above mentioned antennas and shields at the lower ends and to contain transformers 8 and 9 as in FIGS. 3 and 4 within it. By the way, in FIG. 3, the loop antenna 4 and its shield 2 are omitted and only the loop antenna 3 and its shield 2 are shown. However, these loop antennas are connected at the lower ends with the primary of the transformers 8. The secondary winding of the transformer 8 is connected at both ends with feeder line terminals 10, the primary winding of said transformer 9 is connected at both ends respectively with the lower central point of the shield and the lower end of the vertical antenna 5 and the secondary winding of said transformer 9 is connected at both ends with feeder line terminals 11 and none of the loop antennas and their shields is earthed.

Further, in FIG. 4, the primary winding of the transformer 9 is connected at both ends respectively with the neutral point of the primary winding of the transformer 8 connected with the loop antenna 3 at the lower end and with the lower end of the vertical antenna 5. In this drawing, too, the same as in FIG. 3, the loop antenna 2 is omitted. However, the primary winding of the transformer inserted between both ends of the loop antenna is connected at the neutral point with the neutral point of the primary winding of the above mentioned transformer 8.

As in the above described embodiment. in the present invention, the primary winding of the transformer 9 for obtaining a sense determining antenna output is inserted between the lower end of the sense determin ing vertical antenna prlvided at the center of the loop antenna or its shield and the lower central point of the above mentioned loop antenna or its shield without earthing the loop antenna itself or its shield.

Therefore, if the effective height of the vertical antenna is 11 the effective height of the loop antenna or its shield as a vertical antenna is I2 and the electrostatic capacitance between the vertical antenna 5 and the shields 1 and 2 or the loop antennas 3 and 4 is C, the electric current flowing through the primary winding of the transformer 9 will be proportional to 2C (h /1 Therefore, the output of the above described vertical antenna 5 will be equal to the output of a vertical antenna of an effective height of (11 -11 That is to say, the voltage induced by incident waves in the part enclosed with the loop antennas in the vertical antenna 5 will be canceled with the voltage induced in said loop antennas or their shields. Therefore, only the part projecting above the loop antennas will operate effectively. Thus, substantially the same effect as in the case of setting only the vertical antenna of the part projecting above the loop antennas as separated from the upper end of the supporting pole 6 will be obtained and the influence of tuning of said pole will be reduced. That is to say, FIG. 5 shows this operation with a voltage distribution diagram. FIG. 5A is a side view of an antenna device ofthe present invention. In such device, when the supporting pole 6 tunes with incident waves, the distribution of the voltage induced in said supporting pole will be shown by the broken line 12 in FIG. 58. Therefore, the equipotential lines by said voltage will be of such forms as of the broken lines 13 and the density will reduce with the deviation from the point 14 corresponding to the upper end of the supporting pole.

As described above, the present invention is a simple structure wherein a transformer for taking out a sensing antenna output is only inserted between the lower central point of a loop antenna or its shield and the lower end of a vertical antenna without earthing the loop antenna or its shield so that the vertical antenna may be effectively separated from the upper end of the supporting pole. Therefore, even in case the supporting pole or feeder line tunes with incident waves, the influ ence of the induced voltage will be reduced and the sense will be able to be accurately determined.

What is claimed is:

1. An antenna device for direction finders comprising a loop means formed of two loop antennas arranged so as to rectangularly intersect with each other and shields fitted respectively with said antennas, a sense determining vertical antenna provided at the center of said loop means, a hollow insulated base fitted with said loop means at the lower end and a transformer provided within said base so as to take a sense determining output out of its secondary side, the primary winding in said transformer being connected on both sides respectively with the lower central point of said loop means and the lower side of said vertical antenna, all the above mentioned composing members being not

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2408034 *May 14, 1945Sep 24, 1946Standard Telephones Cables LtdDirection finder antenna
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US4433336 *Feb 5, 1982Feb 21, 1984The United States Of America As Represented By The Secretary Of CommerceThree-element antenna formed of orthogonal loops mounted on a monopole
US4540988 *Jun 13, 1983Sep 10, 1985The United States Of America As Represented By The Secretary Of The NavyBroadband multi-element antenna
US5361072 *Feb 28, 1992Nov 1, 1994Codar Ocean Sensors, Ltd.Gated FMCW DF radar and signal processing for range/doppler/angle determination
US5673053 *Aug 24, 1994Sep 30, 1997Allgon AbAntenna coupling device for coupling an antenna of a hand-portable telephone to a remotely located antenna
US5990834 *Aug 29, 1997Nov 23, 1999Codar Ocean Sensors, Ltd.Radar angle determination with music direction finding
US6590523Apr 1, 2002Jul 8, 2003Codar Ocean Sensors, Ltd.Synthesis of total surface current vector maps by fitting normal modes to single-site HF radar data
US6774837Oct 27, 2003Aug 10, 2004Codar Ocean Sensors, Ltd.Ocean surface current mapping with bistatic HF radar
US6856276Mar 28, 2002Feb 15, 2005Codar Ocean Sensors, Ltd.Multi-station HF FMCW radar frequency sharing with GPS time modulation multiplexing
US6924773Sep 30, 2004Aug 2, 2005Codman Neuro Sciences SarlIntegrated dual band H-field shielded loop antenna and E-field antenna
US7209089Jan 21, 2005Apr 24, 2007Hans Gregory SchantzBroadband electric-magnetic antenna apparatus and method
US7239290 *Sep 14, 2004Jul 3, 2007Kyocera Wireless Corp.Systems and methods for a capacitively-loaded loop antenna
US7274338Oct 12, 2005Sep 25, 2007Kyocera CorporationMeander line capacitively-loaded magnetic dipole antenna
US7408517Jan 25, 2006Aug 5, 2008Kyocera Wireless Corp.Tunable capacitively-loaded magnetic dipole antenna
US7427965Feb 13, 2007Sep 23, 2008Kyocera CorporationMultiple band capacitively-loaded loop antenna
US7760151May 25, 2007Jul 20, 2010Kyocera CorporationSystems and methods for a capacitively-loaded loop antenna
US7876270Mar 15, 2007Jan 25, 2011Kyocera CorporationModem card with balanced antenna
US7932871 *Apr 5, 2006Apr 26, 2011Valeo Securite HabitacleOrthogonal loop radiofrequency antenna device
USH1571 *Jun 29, 1994Aug 6, 1996Hansen; Peder M.Dual-feed, dual-mode antenna for mono-directional pattern
EP0684704A2 *Apr 26, 1995Nov 29, 1995AT&T Corp.A diversity antenna for a wrist telephone
EP1643592A1 *Sep 29, 2005Apr 5, 2006Codman Neuro Sciences SÓrlIntegrated dual band H-field shielded loop antenna and E-field antenna
Classifications
U.S. Classification343/728, 343/842, 343/885
International ClassificationH01Q21/29, G01S19/19, G01S1/02
Cooperative ClassificationH01Q21/29, G01S1/02
European ClassificationG01S1/02, H01Q21/29