Passive Phase Multiplication Circuit for Low-Loss Beam Steering
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Solution Overview
Problem
Existing phased arrays require multiple active phase shifters and complex control circuitry, which increase bulk and cost, and existing passive solutions suffer from power loss and inefficiency in phase multiplication.
Innovation Solution
A passive phase multiplication circuit using a network of linear passive directional couplers achieves phase gain through vector sum and difference operations, allowing for phase multiplication without active components, and can be bidirectional for flexible operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If active phase shifters are used in each element of the phased array, then phase control flexibility is improved, but device complexity and cost increase
Solution Approach 1:
The phased array is divided into multiple sub-arrays, each controlled by a single phase shifter. The Rotman lens segments the beamforming function across multiple output ports, allowing each sub-array to be independently controlled with minimal active components while maintaining overall array flexibility.
Solution Approach 2:
A Rotman lens is introduced as an intermediary passive component between the phase shifters and antenna elements. This lens performs the complex beamforming and phase multiplication functions that would otherwise require multiple active phase shifters at each element, thereby reducing overall system complexity while maintaining adaptability.
2Device complexity
If a Rotman lens is used for passive beam steering, then the number of active components is reduced, but continuous smooth beam sweeping capability is lost
Solution Approach 1:
The system combines static passive Rotman lens structures with dynamic phase shifting control. By dynamically adjusting the phase shifters while the beam sweeps through different directions, continuous smooth beam sweeping is achieved despite the fixed passive lens structure, eliminating the limitation of rudimentary discrete switching.
3Adaptability or versatility
If Wilkinson power combiners are used to average phases, then phase multiplication is achieved, but significant power loss occurs
Solution Approach 1:
The patent replaces the resistive power-dissipating Wilkinson combiner approach with a reactive Rotman lens-based system. The lens uses electromagnetic field coupling and phase interference rather than resistive averaging, achieving phase multiplication without the 3dB or greater power losses inherent in Wilkinson combiner architectures.
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 passive phase multiplication circuit provides efficient phase multiplication with reduced power loss and cost, enabling continuous beam steering with minimal active components, suitable for one- or two-dimensional phased arrays.
Implementation Method 1
a network of linear passive directional couplers acting on an input phase difference between input signals which are an input differential signal pair, +θ and −θ, together with a third signal, ρ, which is the average phase of the input differential signal pair, and outputting one or more output signals with magnitude proportional to the input signals and with a phase shift proportional to the input phase difference
Data Source
AI summary
A phase multiplication circuit comprising a phase multiplier comprising a network of linear passive directional couplers acting on the phase difference between a differential signal pair, +θ and −θ, together with a third signal, ρ, which is the average phase of the differential pair and outputting one or more signals with magnitude proportional to the input signals and with a phase shift proportional to the input phase difference.