Artificial Impedance Surface Antenna Steering via Surface Wave Channels
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Solution Overview
Problem
Current two-dimensional electronically-steerable artificial impedance surface antennas are costly and complex, with limitations in operational bandwidth and tunability due to the use of vias and varactors, which restrict their ability to steer beams effectively across a wide frequency range.
Innovation Solution
The antenna system employs a dielectric substrate with surface wave channels and tunable elements, where voltages control the theta steering angle by modulating surface wave impedance, and relative phase differences between surface wave feeds control the phi steering angle, allowing for two-dimensional electronic steering without the need for mechanical components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If vias and varactors are used to control surface wave impedance for beam steering, then the antenna can be electronically steered in two dimensions, but the operational bandwidth is reduced and the device complexity increases
Solution Approach 1:
The antenna surface is segmented into discrete impedance elements arranged in a grid pattern, where each element can be independently controlled. This segmentation allows the complex two-dimensional steering problem to be broken down into simpler, independently controllable units, reducing the overall system complexity while maintaining full two-dimensional steering capability
Solution Approach 2:
The impedance of each surface element is made dynamically可调 through voltage-controlled varactors, allowing the antenna to electronically steer beams in two dimensions without mechanical movement. This dynamic impedance modulation enables real-time beam steering while avoiding the complexity of mechanical steering mechanisms
2Adaptability or versatility
If vias and varactors are used to control surface wave impedance, then the antenna can be electronically steered, but the operational bandwidth is limited due to inductance from vias shifting the surface wave bandgap
Solution Approach 1:
The patent extracts and eliminates the via structures from the antenna design, replacing them with alternative feeding mechanisms. This removal of vias eliminates the parasitic inductance they introduce, which was causing the surface wave bandgap to shift to lower frequencies and limiting the operational bandwidth, while preserving the electronic steering functionality
Solution Approach 2:
The patent changes the impedance parameters of the surface elements by removing inductive via structures and using alternative capacitance control methods. This parameter change eliminates the frequency-shifting effect of via inductance, allowing the antenna to operate over a broader frequency range while maintaining electronic steering capability
3Adaptability or versatility
If a two-dimensional array of impedance elements with voltage control is used, then arbitrary impedance patterns can be created for beam steering in any direction, but the cost and electronic complexity increase
Solution Approach 1:
The patent implements a universal voltage control architecture where the same control network structure serves multiple functions: controlling impedance magnitude, adjusting phase distribution, and enabling beam steering in any direction. This multi-functionality reduces the overall complexity compared to having separate control systems for each function
Solution Approach 2:
The patent uses a simplified voltage control scheme that applies partial control to the impedance elements, focusing only on the essential parameters needed for beam steering rather than controlling all possible impedance parameters. This partial action approach achieves the required arbitrary impedance patterns while reducing control network complexity and cost
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
This configuration enables low-cost, low-complexity two-dimensional electronic steering of the antenna's radiation pattern, expanding the operational bandwidth and tunability, thus overcoming the limitations of existing technologies.
Implementation Method 1
A varactor is a semiconductor element diode that has a capacitance dependent on the voltage applied to this diode
Implementation Method 2
An artificial impedance surface antenna may be implemented by launching a surface wave across an artificial impedance surface
Data Source
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AI summary
An apparatus (100) comprising a plurality of radiating elements (122,123) and a plurality of surface wave feeds (130). Each radiating element in the plurality of radiating elements comprises a number of surface wave channels (125) in which each of the number of surface wave channels is configured to constrain a path of a surface wave. A surface wave feed in the plurality of surface wave feeds is configured to couple a surface wave channel in the number of surface wave channels of a radiating element in the plurality of radiating elements to a transmission line (156) configured to carry a radio frequency signal.