RF Switch-Mixer Isolation for Parasitic Inductance in Multi-Port Circuits
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Solution Overview
Problem
Existing radio frequency (RF) circuits face challenges in isolating unwanted signals from multiple input ports, particularly due to parasitic inductance in semiconductor packages, which complicates signal processing and reduces isolation efficiency.
Innovation Solution
The RF circuit incorporates a switch configuration that distributes aggressor signals into RF components with the same phase, allowing these signals to be offset by a mixer stage, thereby isolating unwanted signals without requiring external elements or direct removal of parasitic inductance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If parasitic inductance is present in the semiconductor package, then the RF circuit can be manufactured with standard packaging, but the impedance increases in higher frequency bands resulting in larger reflected components and reduced isolation performance
Solution Approach 1:
The patent converts the harmful reflected components caused by parasitic inductance into useful signals by intentionally allowing them to pass through the amplifier and enter the mixer. The mixer then processes these reflected components along with the desired signal, effectively utilizing what would otherwise be harmful interference to achieve the desired isolation performance without requiring complex external matching networks.
2Reliability
If external elements are used to remove parasitic inductance, then isolation performance can be improved, but the device complexity and number of external components increase
Solution Approach 1:
The patent extracts the isolation function from external components and relocates it within the RF circuit itself. By using the mixer to process both the desired signal and the reflected components internally, the circuit achieves isolation without requiring external matching networks or additional isolation components, thereby reducing device complexity while maintaining isolation performance.
Solution Approach 2:
The mixer is given a dual function: it not only performs the standard signal mixing operation but also processes the reflected components from parasitic inductance to achieve isolation. This multi-functionality eliminates the need for separate isolation components, reducing overall device complexity while maintaining effective isolation performance.
Data Source
AI summary
An RF circuit including: first and second ports receiving first and second RF signals; a (1-1)-th amplification stage and a (1-2)-th amplification stage connected to the first port and a first ground to amplify the first RF signal; a (2-1)-th amplification stage and a (2-2)-th amplification stage connected to the second port and a second ground to amplify the second RF signal; a (1-1)-th switch connected to the (1-1)-th amplification stage and the second ground, and a (1-2)-th switch connected to the (1-2)-th amplification stage and the second ground; a (2-1)-th switch connected to the (2-1)-th amplification stage and the first ground, and a (2-2)-th switch connected to the (2-2)-th amplification stage and the first ground; and a mixer to mix the first RF signal or the second RF signal with an LO signal, and mix the first RF signal or the second RF signal with the LO signal.