RLC Polyphase I/Q Phase Shifter With Low Error and Insertion Loss
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Solution Overview
Problem
Existing I/Q signal generators, particularly those with RC-polyphase filter structures, face challenges such as large phase or gain errors in 1-stage structures and significant insertion loss in 2-stage structures, which affect accuracy and system performance.
Innovation Solution
The proposed solution is an I/Q signal generating device with a 1-stage RLC polyphase filter structure, which includes resonance circuits with resistors, capacitors in parallel, and inductors connected in a cross configuration. This design aims to minimize phase and gain errors while reducing insertion loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a 1-stage RC-polyphase filter structure is used, then device complexity is reduced, but phase error and gain error increase
Solution Approach 1:
The patent transforms the traditional RC-polyphase filter into an RLC-polyphase filter by adding inductor elements. This parameter change (adding L component) fundamentally alters the filter characteristics, enabling simultaneous achievement of low complexity (1-stage structure) and high precision (reduced phase and gain errors through resonant cancellation effects)
2Measurement precision
If a 2-stage RC-polyphase filter structure is used, then phase accuracy is improved, but insertion loss increases
Solution Approach 1:
By introducing inductor components to create resonant circuits, the patent achieves high phase accuracy in a single stage without requiring multiple cascaded stages. The resonant cancellation effect compensates for phase errors inherently, eliminating the need for 2-stage structures and their associated insertion losses
3Measurement precision
If a 1-stage RLC-polyphase filter structure is used, then phase accuracy is improved, but device complexity increases
Solution Approach 1:
The patent combines resistive, capacitive, and inductive elements into integrated resonance circuits where components serve multiple functions. The inductor both provides resonant cancellation for phase accuracy and works with existing RC elements, merging filtering and phase correction functions into a unified 1-stage structure
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 1-stage RLC polyphase filter structure achieves accurate I/Q signal generation with minimal phase and gain errors, along with reduced insertion loss, thereby improving system performance and enabling easy input/output matching across a wide frequency band.
Implementation Method 1
the value of the inductor and the value of the capacitor may be set to resonate with each other
Data Source
AI summary
An I/Q signal generating apparatus and phase shift apparatus using the same are provided, the I/Q signal generating apparatus including: a first resonance circuit whose one end is connected to a first input terminal and whose other end is connected to a first output terminal; and a second resonance circuit whose one end is connected to the other end of the first resonance circuit or a second input terminal, and whose other end is connected to a second output terminal, wherein the first resonance circuit and the second resonance circuit each include a resistor, a capacitor connected in parallel with the resistor, and an inductor connected in a form of a cross between the resistor and the capacitor.