Passive Phased Array Imager Using Sub-Phase Sampling
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Solution Overview
Problem
Phased array antennas are overly complex and expensive due to the need for active elements, low noise amplifiers, narrow band filters, mixers, and precise phase synchronization, making them difficult to build and maintain.
Innovation Solution
A passive phased array imager using a coplanar waveguide structure with multiple detectors to oversample incoming signals, eliminating the need for local oscillators, mixers, preamplifiers, and phase shifters, and allowing for simpler and less expensive components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional phased array antennas use active elements with LNA, filter, mixer and LO for each antenna element, then measurement precision and imaging capability are improved, but device complexity and manufacturing cost increase significantly
Solution Approach 1:
Multiple antenna elements share common LNAs, filters, and other signal processing components through a combining network. The patent integrates these components into a shared infrastructure rather than dedicating them to individual antenna elements, thereby reducing overall system complexity while preserving measurement precision through coherent signal combination.
Solution Approach 2:
The local oscillator (LO) is distributed to serve multiple antenna elements simultaneously through a phase synchronization network. This universal LO distribution system enables all mixers in the array to operate coherently with a single frequency source, eliminating the need for multiple independent oscillators and reducing system complexity.
2Measurement precision
If each antenna element has its own LNA, mixer and LO with phase synchronization, then imaging quality is improved, but weight and size of the system increase
Solution Approach 1:
The patent merges multiple heavy components into shared infrastructure. By consolidating LNAs, filters, and LO distribution networks into common components served by multiple antenna elements, the total weight of the system is reduced while maintaining the coherent signal processing necessary for high-quality imaging.
3Measurement precision
If precise phase delay control electronics are used to close phase across the array, then phase accuracy is improved, but device complexity and cost increase
Solution Approach 1:
A single phase synchronization network serves all antenna elements in the array, providing coherent phase reference across the entire system. This universal phase control approach maintains phase accuracy for high-quality imaging while avoiding the complexity of independent phase control electronics for each antenna element.
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
Enables the construction of a cost-effective and compact phased array system capable of precise amplitude and phase measurements, reducing size and weight while maintaining high image quality through distributed element waveguides and periodic detector spacing.
Implementation Method 1
The frequency of interest is a resonant frequency dependent on a predetermined length between two adjacent antennas coupled to the coplanar waveguide
Implementation Method 2
a plurality of detectors, disposed across the coplanar waveguide for sampling the received wavefront, and providing multiple output voltages
Implementation Method 3
a coplanar waveguide, disposed in the substrate and coupled to the plurality of antennas
Data Source
AI summary
A passive phased array imager includes a plurality of antennas, disposed on a substrate, for receiving a wavefront from a target; and a coplanar waveguide, disposed in the substrate and coupled to the plurality of antennas. Also included is a plurality of detectors, disposed across the coplanar waveguide for sampling the received wavefront, and providing multiple output voltages to an imaging circuit for displaying information contained in the received wavefront. The plurality of antennas includes at least two dipoles coupled to the coplanar waveguide, and the two dipoles are spaced by a predetermined length to provide a standing wave at a frequency of interest.