Single-layered radial line slot antenna
First Claim
1. An inner-feed-type planar antenna of single-layered structure excited by an axially symmetric mode for propagating radio waves from the center toward an outer periphery within a propagation layer having an antenna surface, comprising:
- (a) an axially symmetric mode waveguide member;
(b) radio-wave connecting means connected to the center of said axially symmetric mode waveguide member;
(c) a plurality of coupling slots formed in said antenna surface and following along a spiral curve on said antenna surface of said axially symmetric mode waveguide member wherein a proportional coefficient of radiation power per unit length in the radial direction is high at the outer periphery and becomes successively lower as the center is approached; and
(d) a continuous spiral terminating slot following along said spiral curve, and provided in the antenna surface at an outer portion of said axially symmetric mode waveguide member, wherein a beginning portion of said continuous spiral terminating slot is located at a position on said spiral curve adjacent to a last slot among said plurality of coupling slots, and a terminating portion of said continuous spiral terminating slot is also disposed on said spiral curve.
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Abstract
An inner-feed-type planar antenna of single-layered structure excited by an axially symmetric mode for propagating radio waves from the center toward the outer periphery within a propagation layer having an antenna surface. If the planar antenna is used for transmission, it is provided with a plurality of coupling slots formed and arrayed in one surface of an axially symmetric mode waveguide member in such a manner that the coupling factor of the external radiation is high at the outer periphery and becomes successively lower as the center is approached. A spiral or ring-shaped terminating slot is provided in the antenna surface at the outer portion of the axially symmetric mode waveguide member. A region not coupled with the outer portion is provided at the center of the antenna surface. Furthermore, the planar antenna is provided with a reflector member arranged along the terminating slot for reflecting a propagating radio wave between the inner and outer portions of the axially symmetric mode waveguide member. A comparatively flat aperture distribution in which the electromagnetic field is uniform can be obtained. In addition, by providing the central portion with a non-radiating region, long-line effect is suppressed and bandwidth enlarged.
49 Citations
11 Claims
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1. An inner-feed-type planar antenna of single-layered structure excited by an axially symmetric mode for propagating radio waves from the center toward an outer periphery within a propagation layer having an antenna surface, comprising:
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(a) an axially symmetric mode waveguide member; (b) radio-wave connecting means connected to the center of said axially symmetric mode waveguide member; (c) a plurality of coupling slots formed in said antenna surface and following along a spiral curve on said antenna surface of said axially symmetric mode waveguide member wherein a proportional coefficient of radiation power per unit length in the radial direction is high at the outer periphery and becomes successively lower as the center is approached; and (d) a continuous spiral terminating slot following along said spiral curve, and provided in the antenna surface at an outer portion of said axially symmetric mode waveguide member, wherein a beginning portion of said continuous spiral terminating slot is located at a position on said spiral curve adjacent to a last slot among said plurality of coupling slots, and a terminating portion of said continuous spiral terminating slot is also disposed on said spiral curve. - View Dependent Claims (2, 3, 4, 5, 6)
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7. An inner-feed-type planar antenna of single-layered structure excited by an axially symmetric mode for propagating radio waves from the center toward an outer periphery within a propagation layer having an antenna surface, comprising:
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(a) an axially symmetric mode waveguide member; (b) radio-wave connecting means connected to the center of said axially symmetric mode waveguide member; (c) a plurality of coupling slots formed in said antenna surface and following along a spiral curve on said antenna surface of said axially symmetric mode waveguide member wherein a proportional coefficient of radiation power per unit length in the radial direction is high at the outer periphery and becomes successively lower as the center is approached; (d) a circular, ring-shaped slot provided in the antenna surface at an outer portion of said axially symmetric mode waveguide member; and (e) a phase adjusting member consisting of dielectric material disposed in a space between a front side and a rear side of said axially symmetric mode waveguide member and in the vicinity or the outer portion of said axially symmetric mode waveguide member for applying a predetermined amount of phase conforming to a circumferential angle. - View Dependent Claims (8, 9)
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10. An inner-feed-type planar antenna of single-layered structure excited by an axially symmetric mode for propagating radio waves from the center toward an outer periphery within a propagation layer having an antenna surface, comprising:
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(a) an axially symmetric mode waveguide member; (b) radio-wave connecting means connected to the center of said axially symmetric mode waveguide member; (c) a plurality of coupling slots formed in said antenna surface and following along a spiral curve on said antenna surface of said axially symmetric mode waveguide member wherein a proportional coefficient of radiation power per unit length in the radial direction is high at the outer periphery and becomes successively lower as the center is approached; (d) a circular, ring-shaped slot provided in the antenna surface at an outer portion of said axially symmetric mode waveguide member; and (e) at least three waveguide regions which, as seen from the center in the radial direction of said axially symmetric mode waveguide member, are a first waveguide region closest to the center, and having a first dielectric constant, a second waveguide region adjacent to and on a circumference of the first waveguide region, and having a second dielectric constant, and a third waveguide region adjacent to and on a circumference of said second waveguide region, and having a third dielectric constant; (f) a phase adjusting member consisting of a dielectric plate, the diameter of which enlarges along a spiral curvature in dependence upon a circumferential angle from the center to the periphery of said waveguide member is arranged inside the radial waveguide formed by a slotted plate and a base plate of said waveguide member, in such a manner that said second dielectric constant being greater than said first dielectric constant, and said second dielectric constant applying a predetermined amount of phase, which conforms to a circumferential angle, to propagating radio waves. - View Dependent Claims (11)
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Specification