Integrated Directional Coupler and Impedance Matching Circuit
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Solution Overview
Problem
Wireless devices face challenges in reducing circuitry and cost while maintaining performance, particularly due to the capacitive nature of switchplexers which degrades performance and increases insertion loss.
Innovation Solution
Integration of a directional coupler and impedance matching circuit in a single output circuit, sharing inductors to reduce circuitry and size, and placing the directional coupler closer to the antenna for improved impedance matching and self-calibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If separate directional coupler and impedance matching circuits are used, then circuit functionality is complete, but circuitry size and cost increase
Solution Approach 1:
The patent combines the directional coupler and impedance matching circuit into a single integrated circuit. The directional coupler includes first and second coupled resonant circuits, while the impedance matching circuit shares the first coupled resonant circuit and adds a second resonant circuit. This merging reduces the number of separate components, decreases circuitry size, and lowers cost while maintaining both directional coupling and impedance matching functionalities.
Solution Approach 2:
The first coupled resonant circuit serves dual purposes: it functions as part of the directional coupler for signal coupling and as part of the impedance matching circuit for impedance transformation. This multi-functionality allows a single circuit element to fulfill multiple roles, reducing overall circuit complexity and component count while preserving performance.
2Ease of operation
If switchplexer with capacitive nature is used, then signal routing is achieved, but performance degrades and insertion loss increases
Solution Approach 1:
The integrated impedance matching circuit acts as an intermediary between the capacitive switchplexer and the antenna. By providing impedance transformation and matching, it compensates for the capacitive effects of the switchplexer, reducing signal reflections and insertion loss while maintaining signal routing functionality.
3Device complexity
If directional coupler is placed farther from antenna, then circuit design is simpler, but impedance matching and self-calibration improve
Solution Approach 1:
The integration of directional coupler and impedance matching circuit allows the coupled resonant circuits to be positioned closer to the antenna while maintaining design simplicity. The shared first coupled resonant circuit enables both functions to work together, achieving good impedance matching and self-calibration performance without requiring the directional coupler to be far from the antenna.
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 integration reduces circuitry, size, and cost while enhancing performance by mitigating the capacitive effects of switchplexers and improving total radiated power control.
Implementation Method 1
a first coupled resonant circuit providing an impedance transformation between the switchplexer and the antenna
Implementation Method 2
a first and a second resonant circuits providing a signal coupling from the switchplexer to the antenna
Data Source
AI summary
An output circuit with an integrated directional coupler and impedance matching circuit is disclosed. In an exemplary design, an apparatus includes a switchplexer and an output circuit. The switchplexer is coupled to at least one power amplifier. The output circuit is coupled to the switchplexer and a load (e.g., an antenna) and includes a directional coupler and an impedance matching circuit sharing at least one inductor. The output circuit performs impedance matching for the load. The output circuit also acts as a directional coupler and provides an input radio frequency (RF) signal as an output RF signal and further couples a portion of the input RF signal as a coupled RF signal. Reusing the at least one inductor for both the directional coupler and the impedance matching circuit may reduce circuitry, size, and cost of the wireless device and may also improve performance.