Communication Module Ground Plane Segmentation for Spurious Emission Control
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Solution Overview
Problem
In high-speed sampling radio frequency modules, such as those in 5G mobile communication systems, the coupling of radio frequency and baseband grounds can lead to spurious emissions due to digital noise, which existing technologies have not effectively addressed.
Innovation Solution
A communication module design that includes a baseband integrated circuit element, a radio frequency integrated circuit element, a radiating element, and inter-ground connection circuits to connect the baseband and radio frequency ground planes, with the second inter-ground connection circuit placed closer to the edges of the planes to weaken noise currents and suppress spurious emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the baseband ground plane and radio frequency ground plane are coupled to enable high-speed sampling, then signal processing capability is improved, but spurious emissions are generated due to digital noise
Solution Approach 1:
The ground connection is segmented into multiple inter-ground connection circuits distributed at different positions between the baseband ground plane and radio frequency ground plane. This segmentation allows different segments to handle different noise currents with different phases, suppressing spurious emissions while maintaining high-speed signal processing capability
Solution Approach 2:
Different regions of the ground connection have different characteristics - the first inter-ground connection circuit provides low-impedance path for RF signals, while the second inter-ground connection circuit positioned at the edge provides specific phase relationship for noise current cancellation. This local differentiation resolves the contradiction between speed and emission control
2Object-generated harmful factors
If the second inter-ground connection circuit is positioned at the edge of the ground planes, then noise current phase cancellation is improved, but manufacturing alignment becomes more difficult
Solution Approach 1:
The second inter-ground connection circuit is deliberately positioned asymmetrically at the edge region of the ground planes rather than at the center. This asymmetric positioning creates the necessary phase difference for noise current cancellation while the patent provides specific design guidelines to maintain manufacturing feasibility
Data Source
AI summary
A feed line connects an RFIC and a radiating element. A baseband ground plane (BB ground) is connected to a ground terminal of a BBIC. A radio frequency ground plane (RF ground) is placed in such a manner as to overlap the BB ground. The RF ground serves as a return path of the feed line. A first inter-ground connection circuit connects the BB ground and the RF ground. Furthermore, a second inter-ground connection circuit connects the BB ground and the RF ground. Connecting parts between these grounds and the second inter-ground connection circuit are arranged closer to the edges of these grounds than connecting parts between these grounds and the first inter-ground connection circuit. The connecting part between the ground and the second inter-ground connection circuit is placed on one side of a certain imaginary straight line that passes substantially the geometric center of the ground.