RF Intermodulation Cancellation Using Phase-Shifted Nonlinear Elements
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Solution Overview
Problem
Current mobile terminals face interference issues due to the generation of third-order intermodulation products in nonlinear electronic components, which hinder simultaneous voice and LTE operations, as these products cannot be easily attenuated and often fall within the receiver's pass bands, rendering the terminal ineffective.
Innovation Solution
An RF system is introduced that includes a first nonlinear element generating inherent IM products and a second nonlinear element generating compensating IM products, with a phase shifter providing a 180° phase shift between them, effectively canceling or reducing the IM products by adjusting the phase shifts to align the compensating IM products with the inherent ones.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two cellular front ends operate simultaneously on different bands, then simultaneous voice and LTE operations are enabled, but third-order intermodulation products are generated that fall within receiver pass bands and cannot be easily attenuated
Solution Approach 1:
The patent applies preliminary anti-action by generating compensating IM products in advance through a second nonlinear element that are specifically designed to cancel the harmful inherent IM products from the first nonlinear element. The phase shifter pre-adjusts the compensating IM products to achieve 180° phase difference, so that when both signals combine, the harmful IM products are cancelled before they can interfere with the receiver operations.
Solution Approach 2:
The patent converts the harmful IM products into a beneficial cancellation mechanism. By intentionally generating additional IM products through the second nonlinear element that are phase-shifted by 180°, the harmful inherent IM products are transformed into a self-cancelling system. The previously harmful IM products become the mechanism for their own elimination, improving simultaneous operation capability.
2Adaptability or versatility
If a single mobile terminal operates on multiple bands simultaneously, then communication versatility is improved, but strong signal interference occurs within the terminal
Solution Approach 1:
The patent introduces a phase shifter as an intermediary element between the two nonlinear elements. This phase shifter mediates the interaction between the inherent IM products and compensating IM products by precisely controlling the phase relationship. The intermediary phase shifter enables the harmful signals to be transformed into beneficial cancellation without requiring direct modification of the nonlinear elements themselves.
3Ease of operation
If nonlinear electronic components are used in the RF system, then signal transmission is enabled, but third-order intermodulation products are generated that degrade mobile terminal operation
Solution Approach 1:
The patent applies parameter changes by modifying the phase parameter of the compensating IM products through the phase shifter. By adjusting the phase parameter to achieve 180° difference, the system transforms the harmful IM products into beneficial cancellation. This parameter modification approach maintains the nonlinear components' signal transmission capability while eliminating their harmful effects on operation reliability.
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 significantly reduces or cancels the intermodulation products, improving the operational capability of mobile terminals to support simultaneous voice and LTE operations by minimizing interference, thereby enhancing the terminal's performance.
Implementation Method 1
a phase shifter that is adapted to provide a phase shift that results in around 180° of phase shift between the inherent IM products and the compensating IM products
Implementation Method 2
The amplitudes of the compensating IM products are substantially equal to amplitudes of the inherent IM products... effectively canceling or reducing the IM products
Data Source
AI summary
An RF system for reducing intermodulation (IM) products is disclosed. The RF system includes a first nonlinear element and a second nonlinear element, wherein the second nonlinear element generates inherent IM products and the first nonlinear element is adapted to generate compensating IM products. Alternatively, the first nonlinear element generates inherent IM products and the second nonlinear element is adapted to generate compensating IM products. The amplitudes of the compensating IM products are substantially equal to amplitudes of the inherent IM products. The RF system further includes a phase shifter that is adapted to provide a phase shift that results in around 180° of phase shift between the inherent IM products and the compensating IM products. The phase shifter is coupled between the first nonlinear element and the second nonlinear element.