Varactor Reflection Phase Shifter for Low-Loss Beam Steering
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Solution Overview
Problem
Existing phase shifters for phased array antennas are complex, large, and lossy, making them impractical for many commercial applications, and they often rely on wave propagation through active media.
Innovation Solution
A phase shifter design using a quadrature hybrid with varactors terminated by identical varactors, where the capacitance is varied by an external bias voltage, and optionally combined with inductors, to achieve a two-port network with minimal reflection and adjustable phase shift, and an electronic switch using a circulator or quadrature hybrid with varactors for low-loss amplitude modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If existing phase shifter designs are used, then phase shifting function is achieved, but device complexity becomes very complicated
Solution Approach 1:
The phase shifter is segmented into distinct functional modules: a quadrature hybrid coupler for signal splitting and combining, and separate varactor diode circuits for phase control. This modular segmentation simplifies the overall design and makes the complex phase shifting function more manageable and practical for commercial applications.
Solution Approach 2:
The patent replaces traditional mechanical or complex electromagnetic phase shifting mechanisms with a simplified electrical control system using varactor diodes. By using voltage-controlled capacitance changes in the varactors rather than complex wave propagation through active media, the design achieves phase shifting with reduced complexity and improved practicality.
2Volume of moving object
If existing phase shifters are used, then phase shifting is achieved, but size becomes large
Solution Approach 1:
The patent merges multiple functions into compact integrated structures. The quadrature hybrid coupler and varactor circuits are designed to work together in a unified compact layout, eliminating the need for separate large components. This merging of functions reduces the overall volume while maintaining the phase shifting capability needed for commercial applications.
3Loss of energy
If existing phase shifters are used, then phase shifting function is achieved, but energy loss becomes high
Solution Approach 1:
The patent substitutes lossy active media-based phase shifting with a passive quadrature hybrid coupler combined with varactor diodes. This substitution eliminates the need for wave propagation through lossy active media, significantly reducing energy loss while maintaining a relatively simple design structure that is practical for commercial use.
4Adaptability or versatility
If quadrature hybrid with varactors is used, then phase shift range is widened, but device complexity increases
Solution Approach 1:
The patent uses varactor diodes that provide dynamic, voltage-controlled capacitance adjustment to achieve a wide phase shift range. The dynamic nature of the varactors allows continuous phase adjustment from 0 to 360 degrees through simple voltage control, maintaining circuit simplicity while maximizing adaptability and phase shift versatility.
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 design provides a compact, low-loss phase shifter with a wide range of phase shifts and reduced complexity, enabling flexible antenna design and improved beam steering capabilities.
Implementation Method 1
The capacitance of the varactors may be changed by an external bias voltage
Implementation Method 2
port 2 receives a half of the incident power with −90 degree phase shift, the other half with −180 degree phase shift is transmitted to port 3
Implementation Method 3
an inductor may be connected either in parallel, or in series, with each of the varactors to create a resonant condition
Data Source
AI summary
A phase shifter that relies on a reflected wave from a load such as a varactor with a capacitance varied by an external bias voltage is provided. The phase shift does not depend on the wave propagation through an active medium. The input RF signal is sent to the variable loading and the reflected wave from the load is channeled to the output port via a network that takes the input signal without much reflection to the input terminal but passes most of the power from the variable load to the output terminal with a phase change depending on the variable bias input of the loading. Such network to steer the input to the variable loading and send the signal reflected from the loading to the output port without much reflection includes a quadrature hybrid or a circulator.