Differential-Fed Patch Antenna for Cross-Polarization Cancellation
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Solution Overview
Problem
Patch antennas emit significant cross-polarized radiation, which reduces power efficiency in wireless communication systems by requiring more power to achieve desirable co-polarized radiation, and this is attributed to an imbalance of electric fields along the radiation edges.
Innovation Solution
Implement a patch antenna design with multiple feeds having a phase shift, such as a 180-degree differential feed, connected at different points along the patch antenna, and incorporate an opening at the center to balance the electric fields, reducing cross-polarized radiation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a conventional patch antenna is used, then the antenna structure is simple, but cross-polarized radiation is significant which reduces power efficiency
Solution Approach 1:
The patch antenna is divided into multiple radiating edges with different feed points. Each edge is fed independently through a differential feed structure, allowing separate control of electric fields along different edges. This segmentation enables cancellation of cross-polarized radiation while maintaining a relatively simple overall antenna structure.
Solution Approach 2:
The invention changes the feeding parameters by introducing a differential feed with 180-degree phase shift between opposite edges. This parameter change in the excitation mode transforms the electric field distribution, causing cross-polarized fields to cancel while co-polarized fields reinforce, thereby improving power efficiency without major structural complexity.
2Object-generated harmful factors
If multiple feeds with phase shift are implemented, then cross-polarized radiation is reduced, but the antenna and circuitry footprint increases
Solution Approach 1:
The differential feed structure merges the feeding of opposite edges into a single balanced feed point. By combining the feed lines and using a differential signaling approach, the invention achieves cross-polarization cancellation without requiring separate feed structures for each edge, thereby minimizing the additional footprint.
Solution Approach 2:
The differential feed structure serves multiple functions simultaneously: it provides excitation to multiple radiating edges, creates the necessary phase differences for cross-polarization cancellation, and maintains a compact form factor. This multi-functionality reduces the need for additional dedicated components that would increase 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 improved patch antenna design achieves near-full cancellation of cross-polarized radiation, enhancing power efficiency and reducing the footprint of the antenna and accompanying circuitry.
Implementation Method 1
Implement a patch antenna design with multiple feeds having a phase shift, such as a 180-degree differential feed
Implementation Method 2
incorporate an opening at the center to balance the electric fields, reducing cross-polarized radiation
Data Source
AI summary
A playback device is configured to transmit and receive signals via a patch antenna coupled to a wireless radio. The patch antenna is configured to reduce cross-polarized radiation and comprises an electrically conductive ground plane, a substrate disposed on the ground plane, and a radiator disposed on the substrate. The radiator comprises a first portion and a second portion, wherein the first portion of the radiator is coupled through an opening in an interior region of the patch antenna to a first leg of a differential feed. The differential feed is configured to provide a signal to drive the radiator. The patch antenna also comprises a delay element, wherein the second portion of the radiator is coupled via the delay element and further through the opening of the patch antenna to a second leg of the differential feed.