High-Frequency Module Resonance Circuit for TX/RX Isolation
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Solution Overview
Problem
Existing high frequency modules face challenges in maintaining isolation between transmission and reception circuits due to parasitic capacitance in switches, which can damage the reception circuit, especially with large transmission signals, and there is a need to reduce the size of these modules.
Innovation Solution
A high frequency module design incorporating a transmission line transformer and capacitor forms a parallel resonance circuit during transmission, preventing signal leakage to the reception circuit, and functions as an inductor for impedance matching during reception, eliminating the need for separate impedance matching inductors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a switch including a semiconductor is used for switching between transmission and reception circuits, then switching functionality is achieved, but parasitic capacitance is generated causing isolation degradation
Solution Approach 1:
A transmission line transformer is introduced as an intermediary component between the switch and the transmission line. This transformer mediates the signal transmission by providing impedance transformation and isolation, thereby reducing the impact of parasitic capacitance from the switch on the transmission line while maintaining switching functionality.
Solution Approach 2:
The invention changes the impedance parameters by introducing a transmission line transformer with specific impedance ratios. The transformer provides impedance transformation that compensates for the parasitic capacitance effects, improving isolation characteristics while maintaining the switching operation.
2Reliability
If separate inductors are provided for impedance matching in reception circuit, then impedance matching is improved, but module size increases
Solution Approach 1:
The transmission line transformer is designed to serve multiple functions: it provides impedance transformation during transmission mode and acts as an inductor for impedance matching during reception mode. This multi-functionality eliminates the need for separate inductors, thereby reducing module size while maintaining impedance matching performance.
Solution Approach 2:
The invention merges the impedance transformation function and the inductance function into a single transmission line transformer component. By combining these functions, the design eliminates the need for separate inductors and reduces the overall module size while maintaining both impedance matching capabilities.
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 design improves isolation characteristics between transmission and reception circuits while reducing the module's size by integrating the transformer for both functions, thus minimizing signal loss and module size.
Implementation Method 1
a first capacitor and a second switch that are connected in series between the input terminal and the output terminal; and a third switch that is connected between the output terminal and a ground terminal. When the first switch is electrically connected, the first capacitor and the second transmission line form a parallel resonance circuit.
Implementation Method 2
at the time of reception, the transmission line transformer functions as an inductor for impedance matching
Data Source
AI summary
An input terminal, an output terminal, and an antenna terminal; a first transmission line transformer that includes a first transmission line, a second transmission line, and a third transmission line; a first capacitor and a first switch that are connected in series between the input terminal and the output terminal; and a second switch that is connected between the output terminal and a ground terminal, are provided. The first transmission line includes a first end portion that is connected to the input terminal and a second end portion. The second transmission line includes a third end portion that is connected to the output terminal and a fourth end portion that is connected to the input terminal. The third transmission line includes a fifth end portion that is connected to the second end portion and a sixth end portion that is connected to the antenna terminal.