US 5,479,176 A · Multiple-element driven array antenna and phasing method

Abstract

An antenna array for direction-agile applications, such as r.f. packet mesh networks, employs a plurality of quarter-wave radiators disposed normally to a ground plane on a dielectric backing and switching elements for selecting a desired receiving direction and transmission direction and minimizing interference from signals in opposing directions. A control system selects and switches direction rapidly enough to receive and transmit digipeating signals in selected different directions using the phasing and switching elements. A specific embodiment employs eight radiators of 0.2625 electrical wavelengths (quarter wave plus 5%) disposed equidistant along a circle within a circular ground plane in a pattern which is 1/4 wavelength from the outer boundary of the ground plane, each radiator being disposed at least 0.15 wavelengths to about 0.25 wavelengths from adjacent radiators in a circular pattern. The antenna is characterized by eight electronically switchable radiating directions (at 45.degree. intervals) with at least 20 dB front to back ratio and a 3 dB beamwidth of 64.degree.. Pairs of radiators form parasitic elements, driven elements and reflectors with spacing selected as a modest compromise from the ideal spacing to allow electronically selectable directionality using identically-spaced elements acting as driven elements, parasitic elements and reflector elements. The driven elements are slightly reactively fed.

Claims13

Dependent claims

A multiple-element array antenna system comprising:

a conductive ground plane base having an outer boundary;
eight equal-length radiating elements of at least one-quarter wavelength electrical length at a selected operating frequency, each said radiating element being disposed with a first end adjacent said ground plane and a second end protruding normal to said ground plane, each said radiating element being arranged equidistant along on a circle within said conductive ground plane, said circle being disposed at least one quarter wavelength from said outer boundary in an equally space pattern, wherein two of said radiating elements are selectable as type 1 elements and two of said radiating elements are selectable as type 2 elements, while unused elements are effectively electrically isolated, wherein said two type 1 elements are driven elements and are spaced from one another by three element positions in one circular direction and five element positions in the opposing circular direction on said circle, wherein said two type 2 are spaced from one another by three element positions in one circular direction and five element positions in the opposing circular direction on said circle, and wherein each said driven element is spaced by one element position from one of said type 2 elements;
a plurality of feed means, each said feed means being electrically coupled to corresponding element feedpoints at said first ends;
and
switching means for gating r.f. energy to selected ones of said feed means;
said pattern of said radiating elements and said switching means governing a preselected switchable radiating pattern having a maximized front-to-back ratio.

3 more elements

A method for receiving and transmitting r.f. energy using a multiple-element array antenna system, said antenna system comprising a conductive ground plane base having an outer boundary;

eight equal-length radiating elements of at least one-quarter wavelength electrical length at a selected operating frequency, each said radiating element being disposed with a first end adjacent said ground plane and a second end protruding normal to said ground plane, each said radiating elements being arranged equidistant along on a circle within said conductive ground plane, said circle being disposed at least one quarter wavelength from said outer boundary in an equally spaced pattern, wherein two of said radiating elements are selectable as type 1 elements and two of said radiating elements are selectable as type 2 elements, while unused elements are effectively electrically isolated, wherein said two type 1 elements are driven elements and are spaced from one another by three element positions in one circular direction and five element positions in the opposing circular direction on said circle, wherein said two type 2 are spaced from one another by three element positions in one circular direction and five element positions in the opposing circular direction on said circle, and wherein each said driven element is spaced by one element position from one of said type 2 elements;
a plurality of feed means, each said feed means being electrically coupled to corresponding element feedpoints at said first ends;
and
switching means for gating r.f. energy to selected ones of said feed means;
said pattern of said radiating elements and said switching means governing a preselected switchable radiating pattern having a maximized front-to-back ratio, said method comprising:
activating first pairs of switching means to establish directionality of a first direction for said antenna array;
receiving an r.f. signal from said first direction;
thereafter
activating second pairs of switching means while deactivating said first pairs to establish directionality of a second direction;
and
transmitting a representation of said r.f. signal in said second direction.

8 more elements

Dependencies are inferred from the claim text.

Multiple-element driven array antenna and phasing method

Life of this patent

Multiple-element driven array antenna and phasing method

Life of this patent

Abstract

Claims13