Reflection-Type Phase Shifter Using Tunable Transmission-Line Loads
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Solution Overview
Problem
Existing reflection-type phase shifters lack an efficient means to tune the reflection coefficient for achieving desired phase shifts in wireless communication applications, particularly in phased-array receivers and transmitters.
Innovation Solution
The implementation of a reflection-type phase shifter using a quadrature coupler with tunable transmission lines as reflection loads, allowing for adjustable impedance and effective electrical length to control the reflection coefficient and achieve desired phase shifts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional capacitors are used as reflection loads in a reflection-type phase shifter, then the phase shift can be achieved by tuning capacitance, but the tuning mechanism becomes complex and difficult to control precisely
Solution Approach 1:
The patent changes the fundamental parameter used for tuning from capacitance value to transmission line electrical length. By using a transmission line with adjustable electrical length (via movable shorting piston or phase shifter), the reflection coefficient's phase component can be controlled directly and precisely without complex capacitor tuning mechanisms, thereby achieving precise phase shift control while simplifying the tuning mechanism
Solution Approach 2:
The patent replaces the mechanical/electrical tuning of capacitor values with a mechanical transmission line structure where the electrical length is adjusted by physically moving a shorting piston or using a dedicated phase shifter mechanism. This substitution provides more direct and precise control over the reflection coefficient's phase component, improving phase shift precision while making the tuning mechanism more manageable
2Adaptability or versatility
If transmission lines are used as reflection loads, then the electrical length can be adjusted to control the reflection coefficient, but the physical size of the device increases
Solution Approach 1:
The patent employs nested transmission line structures where inner transmission lines are placed within outer transmission lines, or where the adjustable electrical length mechanism is nested within the overall phase shifter structure. This nesting allows for compact implementation of the required electrical length adjustments without proportionally increasing the overall device footprint, thereby achieving good reflection coefficient adjustability while controlling physical size
Solution Approach 2:
The patent transitions from controlling phase shift through one-dimensional capacitance value adjustment to using transmission line electrical length control, which introduces a spatial dimension (physical length of transmission line) as the control parameter. This dimensional change provides continuous and precise adjustment of the reflection coefficient while the compact nested structure manages the physical space requirements
3Reliability
If the reflection coefficient is precisely tuned for desired phase shifts, then beamforming performance improves, but the device becomes more sensitive to manufacturing variations and environmental changes
Solution Approach 1:
The patent implements a dynamically adjustable transmission line structure where the electrical length can be tuned after manufacturing. This dynamic capability allows for post-fabrication calibration and compensation of manufacturing variations, ensuring reliable beamforming performance without requiring extremely tight manufacturing tolerances. The system can adapt to environmental changes through real-time adjustment of the transmission line electrical length
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 approach enables easy and efficient control of phase shifts in reflection-type phase shifters, facilitating desired phase shifts for applications like beamforming in phased-array systems, enhancing their performance in wireless communication.
Implementation Method 1
The first reflection load is electrically connected to the through port for reflecting the first fraction of the input signal to thereby generate the first reflected signal
Data Source
AI summary
A reflection-type phase shifter is provided. The reflection-type phase shifter has a coupler, a first reflection load, and a second reflection load. The coupler has an input port for receiving an input signal and an isolated port for outputting an output signal due to a first reflected signal at a through port and a second reflected signal at a coupled port. The first reflection load reflects the first fraction of the input signal to thereby generate the first reflected signal. The second reflection load reflects the second fraction of the input signal to thereby generate the second reflected signal. In addition, at least one of the first and second reflection loads is equivalent to a transmission line.