Wideband asymmetric slot antenna
The present application generally relates to antennas embedded in or on glass structures. More specifically, the application teaches a wideband coplanar antenna employing a slot shape in the ground plane configured to accomplish a broadband frequency response wherein the two axis of symmetry in the antenna design are fragmented in order to maximize resonances of RF currents over broader frequency bands.
1. A vehicular communications system comprising:
a planar dielectric substrate having a first side interior to a vehicle and a second side exterior to a vehicle wherein the planar dielectric substrate is a vehicle windshield;
a transceiver;
a slot antenna structure formed on the second side of the planar dielectric substrate wherein the slot antenna structure is asymmetrical in a first direction, wherein the slot antenna structure has a first tuning stub formed within the slot antenna structure and a second tuning stub formed within the slot antenna structure and wherein the first tuning stub and the second tuning stub are asymmetrical in the first direction wherein the slot antenna structure is positioned such that at least one surface wave is coupled to the dielectric material and wherein the surface wave propagates in a path parallel to the first direction; and
a coplanar waveguide feed, formed on the second side of the planar dielectric substrate, coupled to the transceiver and the first tuning stub and the second tuning stub wherein the first tuning stub is longer than the second tuning stub.
2. The vehicular communications system of claim 1 wherein the slot antenna structure is asymmetrical in a second direction.
3. The vehicular communications system of claim 1 wherein the slot antenna structure is formed by an absence of conductive material within a plane of conductive material.
4. The vehicular communications system of claim 1 wherein the slot antenna structure is bow tie shaped.
5. The vehicular communications system of claim 1 wherein the first tuning stub has a first length in the first direction and the second tuning stub has a second length in the first direction and wherein the first length is greater than the second length.
6. The vehicular communications system of claim 1 wherein slot antenna structure has a narrowed region proximate to a coupling point of the coplanar waveguide feed and the first tuning stub.
7. The vehicular communications system of claim 1 wherein slot antenna structure has a narrowed region proximate to a coupling point of the coplanar waveguide feed and the first tuning stub.
8. The vehicular communications system of claim 1 wherein the slot antenna structure is approximately 122 mm by 500 mm.