Dual Mode Patch Antenna Cross-Pol Attenuation via Cancelling Vector
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Solution Overview
Problem
Existing square planar patch antennas with two orthogonal ports suffer from degraded cross-pol attenuation due to higher modes and unbalanced port impedances, limiting their effectiveness in modern telecom and radar systems, which require excellent radiation efficiency, orthogonal polarization capabilities, and high cross-pol isolation across the full system bandwidth.
Innovation Solution
A dual mode compensated patch antenna design featuring an active patch with two orthogonal ports and a passive patch on a second substrate, combined with a conductive boundary wall that includes a compensating dual mode discontinuity, such as a notch, to create a cancelling vector that improves cross-pol attenuation and port-to-port isolation without adding signal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two orthogonal ports are added to a square planar patch antenna, then the antenna can support orthogonal polarizations, but the cross-pol attenuation degrades to insufficient levels
Solution Approach 1:
The patent introduces an asymmetric perturbation element (such as an L-shaped metallic structure or slot) positioned at a specific location on the patch antenna. This asymmetric feature creates a dual-mode coupling effect that generates a cancelling vector to counteract the harmful higher modes responsible for cross-polarization contamination, thereby improving cross-pol attenuation while maintaining orthogonal polarization support
Solution Approach 2:
The patent pre-compensates for the expected cross-pol degradation by incorporating a cancelling vector mechanism that actively counteracts the harmful higher modes before they can significantly degrade performance. The perturbation element is designed to generate equal and opposite field components that neutralize the cross-polarization effects
2Object-affected harmful factors
If balanced excitation with four symmetrical ports is used, then cross-pol attenuation improves, but signal loss increases due to feed network complexity
Solution Approach 1:
The patent extracts and eliminates the need for complex balanced feed networks by using a simpler unbalanced excitation approach combined with a cancelling vector mechanism. This removes the source of signal loss associated with multiple feed lines and phase shifters while achieving the desired cross-pol attenuation through the asymmetric perturbation element
Solution Approach 2:
The patent creates a simplified version of the balanced excitation effect by using a single or dual port configuration with a cancelling vector that replicates the cross-pol suppression performance of complex balanced feeds without requiring the corresponding complex feed network infrastructure
3Ease of manufacture
If manufacturing errors occur in patch antennas, then performance degrades, but existing designs are highly sensitive to such errors
Solution Approach 1:
The patent designs the cancelling vector mechanism to be inherently robust against manufacturing variations. The asymmetric perturbation element is positioned and dimensioned to provide a wide tolerance window where performance remains stable, effectively cushioning against the impact of manufacturing errors before they can significantly degrade antenna performance
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 achieves very high cross-pol attenuation (up to 40 dB) across the full bandwidth, maintains efficiency, and allows for electronic scanning without frequency squint, while being tolerant to manufacturing errors and simple in design, thus meeting the stringent requirements of modern telecommunications and space-borne applications.
Implementation Method 1
Systems, apparatus and methods for transmitting and receiving electromagnetic radiation
Implementation Method 2
the two orthogonal ports creating a dual mode coupling vector
Data Source
AI summary
A dual mode patch antenna is described herein. The dual mode patch antenna includes an active patch mounted on a first substrate, the active patch having two orthogonal ports located on corresponding X, Y axes of symmetry intersecting at an axis zero located at a center of the active patch, the two orthogonal ports creating a dual mode coupling vector. The dual mode patch antenna also includes a passive patch positioned on top of the active patch, the passive patch mounted on a second substrate, a ground plane positioned below the first substrate, and a conductive boundary wall defining a boundary around the patch antenna, the conductive boundary wall contacting the ground plane below the active patch. The conductive boundary wall includes a compensating dual mode discontinuity that creates a cancelling vector equal in amplitude to the intrinsic, built-in dual mode coupling vector to improve cross-pol attenuation and/or port-to-port isolation of the antenna.