Patch Antenna with Closed-Curve Slot for Vertical Polarization
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Solution Overview
Problem
Existing patch antennas face challenges in achieving vertical polarization, uniform radiation patterns in the azimuth plane, and significant gain at zero elevation degrees, which are essential for various frequency bands like GPS and DSRC.
Innovation Solution
A patch antenna design featuring a closed-curve slot and parasitic slots, with a dual-band capability, utilizing a conductive patch, ground plane, and dielectric substrates, along with specific feed mechanisms to generate vertically-polarized and circularly-polarized radiation patterns, optimized for 5.9 GHz DSRC and 1.575 GHz GPS bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional patch antenna design is used, then the structure is simple, but vertical polarization and uniform radiation pattern cannot be achieved
Solution Approach 1:
The patch antenna is divided into multiple segments: a rectangular patch, a cross-shaped slot etched in the patch, and four parasitic slots positioned around the patch. This segmentation allows each element to contribute specifically to achieving vertical polarization and uniform radiation pattern, resolving the contradiction between structural simplicity and polarization performance.
Solution Approach 2:
The cross-shaped slot and four parasitic slots introduce asymmetric geometric features to the otherwise rectangular patch structure. This controlled asymmetry enables the antenna to achieve vertical polarization and uniform azimuth radiation pattern by creating specific current distributions and field patterns that symmetric designs cannot produce.
2Reliability
If parasitic slots are placed close to the closed-curve slot, then coupling is enhanced, but mutual interference increases
Solution Approach 1:
The closed-curve slot acts as an intermediary element between the rectangular patch and the four parasitic slots. It couples the excitation from the patch to the parasitic slots while controlling the interaction, thereby achieving uniform radiation pattern without excessive mutual interference. The slot serves as a mediator that manages the electromagnetic coupling between adjacent elements.
3Adaptability or versatility
If a single-band antenna is used, then the design is simpler, but multi-frequency band operation cannot be achieved
Solution Approach 1:
The antenna structure is designed to perform multiple functions: the rectangular patch and cross-shaped slot provide resonance for one frequency band, while the same structure combined with the four parasitic slots provides resonance for a second frequency band. This multi-functionality allows dual-band operation without requiring completely separate antenna structures, thereby limiting the increase in complexity.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design achieves a vertically-polarized radiation pattern with uniformity in the azimuth plane and reasonable gain at zero elevation degrees, enabling efficient communication in both GPS and DSRC frequency bands, facilitating integration into a single on-board unit for vehicle applications.
Implementation Method 1
a feed mechanism adapted to supply an excitation signal to the inner portion of the conductive patch
Implementation Method 2
a dielectric substrate disposed between the conductive patch and the ground plane
Data Source
AI summary
A patch antenna for achieving a vertically-polarized radiation pattern is described. The patch antenna includes a closed-curve slot within which a signal feed point is located. Parasitic slots are disposed outside or inside the closed-curve slot. In one embodiment, the closed-curve slot is a ring slot and the parasitic slots are arc slots having a common center point with the ring slot. The antenna may further include a lower patch capable of producing a different radiation pattern with different polarization and at a different frequency band, to result in a dual-band antenna. The dual-band antenna may operate in the 5.9 GHz DSRC and 1.575 GHz GPS bands.