Digital Phase Shifter Layout for Weak Reflection Averaging
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Solution Overview
Problem
Digital phase shifters with cascaded digital phase shift circuits experience phase shift amount distributions due to weak reflections at connection portions, even with suitable impedance matching, which affects their performance.
Innovation Solution
A digital phase shifter design that includes cascaded digital phase shift circuit groups connected via bend-type connection portions, where capacitors are connected in parallel to the connection lines and signal lines to average the phase shift amounts caused by weak reflections, and electronic switches control the flow of return currents through inner and outer lines to manage delay modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a digital phase shifter uses a switched capacitor network with binary-weighted capacitors, then the phase shifter can be implemented with a manageable number of components, but the capacitor values become very large for higher resolution phase shifts
Solution Approach 1:
The capacitor network is divided into multiple groups, where each group contains capacitors with the same value. This segmentation allows the use of smaller, repeated capacitor units instead of one large capacitor per binary weight, resolving the contradiction between manageable component count and large capacitor values.
Solution Approach 2:
The invention changes the parameter of capacitor values from large binary-weighted values to smaller repeated values organized in groups. By adjusting the organization structure rather than the fundamental binary weighting, the capacitor values become manageable while maintaining the required phase shift resolution.
2Measurement precision
If a digital phase shifter achieves high phase shift resolution, then the phase control precision is improved, but the number of capacitors and switches required increases exponentially
Solution Approach 1:
The phase shifter is segmented into multiple groups of capacitors, where each group contributes a portion of the total phase shift. This segmentation allows high resolution to be achieved by combining multiple smaller contributions rather than using a single large-capacity binary-weighted structure, thereby reducing the exponential growth of components.
Solution Approach 2:
Capacitors with the same value are reused across multiple groups, making each capacitor design universal. This multi-use approach reduces the total number of unique capacitor values needed while maintaining high phase shift resolution through the combined effect of multiple groups.
3Manufacturing precision
If the capacitor network is organized into multiple groups with identical capacitors, then the manufacturing precision and component matching are improved, but the network structure becomes more complex
Solution Approach 1:
The capacitor network is explicitly segmented into multiple groups, where each group contains capacitors of identical value. This segmentation improves manufacturing precision by allowing standardized capacitor values to be used throughout, simplifying component matching and selection while the group organization manages the structural complexity.
Data Source
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AI summary
A digital phase shifter includes a bend-type connection portion configured to connect a first digital phase shift circuit located at an end of a first digital phase shift circuit group and a second digital phase shift circuit located at an end of a second digital phase shift circuit group and include a third digital phase shift circuit. A capacitor is connected in parallel to at least one of a first connection line of a first connection portion, a first connection line of a second connection portion, a region in a vicinity of a connection position between two digital phase shift circuits constituting a first digital phase circuit group, and a region in a vicinity of a connection position between two adjacent digital phase shift circuits constituting a second digital phase circuit group.