Antenna Impedance Matching Circuit Using Parallel Transmission Lines
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Solution Overview
Problem
Current antenna impedance matching circuits using capacitors and inductors result in signal loss and reduced antenna efficiency due to the introduction of additional loss mechanisms.
Innovation Solution
An antenna impedance matching circuit comprising a first transmission line with a specific capacitive length and a second transmission line with a specific inductive length, connected in parallel with open or shorted terminals, replacing traditional chip capacitors and inductors to match the antenna impedance with the feeder line impedance, thereby minimizing signal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional capacitors and inductors are used for antenna impedance matching, then the antenna can be matched to the feeder line impedance, but signal loss increases and antenna efficiency decreases
Solution Approach 1:
The patent changes the fundamental parameters of the matching circuit by replacing discrete capacitors and inductors with transmission lines of specific lengths. The transmission line lengths are carefully selected to provide the required reactance values, fundamentally changing how impedance matching is achieved from component-based to geometry-based matching.
Solution Approach 2:
The patent substitutes the mechanical/electrical component system (capacitors and inductors) with an electromagnetic field-based system (transmission lines). The transmission lines utilize their inherent distributed inductance and capacitance to provide the matching function, eliminating the need for separate reactive components that introduce loss.
2Reliability
If capacitors and inductors are used in the matching circuit, then impedance matching can be achieved, but additional loss mechanisms are introduced reducing overall efficiency
Solution Approach 1:
The patent extracts the reactive elements (capacitors and inductors) from the matching circuit and replaces them with the transmission line structure itself. The transmission line's distributed parameters provide the necessary reactance without requiring separate reactive components, thereby eliminating their associated losses.
Solution Approach 2:
The patent merges the impedance matching function with the transmission line structure that already exists in the antenna system. Instead of adding separate matching components, the matching function is integrated into the transmission line geometry, reducing the total number of components and potential loss sources.
3Reliability
If conventional matching components are used, then the antenna can be connected to the feeder line, but power transmission is reduced and reflected waves occur
Solution Approach 1:
The patent changes the matching approach from using discrete components with fixed parameters to using transmission lines where the electrical length and characteristic impedance can be precisely controlled. This allows for optimized power transfer by carefully selecting transmission line parameters to achieve perfect matching at the operating frequency.
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 configuration reduces signal loss and improves antenna radiation efficiency by ensuring matched impedance between the antenna and the feeder line, resulting in higher power transmission and reduced reflection coefficients.
Implementation Method 1
a first transmission line, wherein the first transmission line having a first specific length that makes the first transmission line capacitive
Implementation Method 2
a second transmission line, wherein the second transmission line having a second specific length that makes the second transmission line inductive
Data Source
AI summary
Disclosed is an antenna impedance matching circuit, an antenna system, a printed circuit board, and a terminal. The antenna impedance matching circuit comprises: a first transmission line having a first specific length such that the first transmission line is capacitive, and a second transmission line having a second specific length such that the second transmission line is inductive. In particular, the first transmission line and the second transmission line are connected in parallel, and terminals of the first transmission line and the second transmission line are open or shorted.