Beam Tilting Patch Antenna Higher Order Resonance Mode
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Solution Overview
Problem
Existing patch antennas for receiving circularly polarized RF signals from satellites face challenges in low elevation angles, particularly when mounted on vehicle windows, due to signal obstruction by the vehicle roof, and have a large 'footprint' that obstructs the driver's view and degrades signal quality.
Innovation Solution
A patch antenna design with a radiating element and phase shift circuits that generate a circularly polarized radiation beam solely in a higher order mode, allowing the radiation beam to be tilted away from the axis perpendicular to the radiating element, reducing the antenna's footprint and improving signal reception at low elevation angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional patch antenna is used to receive circularly polarized RF signals, then the antenna can receive signals at high elevation angles, but the antenna cannot effectively receive signals at low elevation angles due to roof obstruction
Solution Approach 1:
The patent changes the operational mode parameter from fundamental mode to higher order mode (specifically TM22 mode), which fundamentally alters the radiation pattern characteristics. This parameter change enables the radiation beam to tilt away from the normal direction, allowing effective reception at low elevation angles where conventional antennas fail due to roof obstruction.
2Reliability
If the radiating element size is increased to improve signal reception, then the antenna gain is improved, but the antenna footprint increases and obstructs the driver's view
Solution Approach 1:
By changing the operational mode to higher order mode, the patent achieves a fundamental decoupling between antenna footprint and signal reception quality. The higher order mode operation allows a small footprint radiating element to produce a tilted radiation beam with sufficient gain for low elevation angle reception, eliminating the need to increase physical size.
3Area of stationary object
If the radiating element size is decreased to reduce footprint, then the driver's view is improved, but the antenna cannot effectively receive signals at low elevation angles
Solution Approach 1:
The patent changes the operational mode parameter to higher order mode, which fundamentally alters the relationship between antenna size and radiation characteristics. This parameter change enables a small radiating element to produce a tilted radiation beam that can effectively receive signals at low elevation angles, overcoming the limitation that normally prevents small antennas from receiving low-angle signals.
4Device complexity
If a conventional patch antenna design is used, then the antenna structure is simple, but the radiation beam cannot be tilted away from the normal direction
Solution Approach 1:
The patent changes the operational mode from fundamental to higher order mode, which naturally produces a tilted radiation beam without requiring complex structural modifications. The feed port spacing and phase shift circuits work with the higher order mode to achieve beam tilting while maintaining relatively simple antenna geometry.
5Area of stationary object
If feed ports are spaced closer together to reduce footprint, then the antenna size is reduced, but the radiation pattern cannot be properly controlled for low elevation reception
Solution Approach 1:
By changing to higher order mode operation, the patent enables proper radiation pattern control with closely spaced feed ports. The higher order mode's inherent field distribution characteristics allow the spaced feed ports to effectively control the radiation pattern and achieve beam tilting, even when the spacing is reduced to minimize footprint.
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 solution enables effective reception of circularly polarized RF signals at low elevation angles with a smaller antenna footprint, maintaining good visibility for the driver and reducing signal degradation, making it suitable for automotive applications.
Implementation Method 1
At least one phase shift circuit is electrically connected to at least one of the plurality of feed lines for phase shifting a base signal to achieve a phase-shifted signal
Implementation Method 2
the radiating element is excitable to generate a circularly polarized radiation beam solely in a higher order mode at a desired frequency
Data Source
AI summary
A patch antenna receives circularly polarized RF signals from a satellite. The antenna includes a radiating element. A plurality of feed lines feed the radiating element at a plurality of feed points. The feed points are spaced apart to generate a circularly polarized radiation beam solely in a higher order mode at a desired frequency. The antenna may include a plurality of parasitic structures. The feed point spacing and/or the parasitic structures tilt the radiating beam away from an axis perpendicular to the radiating element. Thus, the patch antenna provides excellent RF signal reception from satellites at low elevation angles.