RF Module Layout for Carrier Aggregation Band Isolation
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Solution Overview
Problem
Reducing the size of radio-frequency modules that perform carrier aggregation leads to decreased isolation characteristics, as harmonic components from low-band amplifier circuits can leak into high-band receive circuits due to electromagnetic and electrostatic coupling, which existing solutions fail to effectively suppress beyond ground pattern pathways.
Innovation Solution
The placement of a first separator circuit, defined by SAW filters, between the low-band and high-band amplifier circuits on a substrate, along with strategic positioning and use of via-conductors, switches, and impedance matching circuits, reduces coupling between these circuits, thereby minimizing harmonic leakage and improving isolation characteristics across bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the size of a radio-frequency module is reduced, then miniaturization is achieved, but isolation characteristics between bands deteriorate due to increased coupling and harmonic leakage
Solution Approach 1:
The radio-frequency module is divided into distinct low-band and high-band regions with separate amplifier circuits, matching circuits, and ground patterns. This segmentation prevents harmonic components from the low-band amplifier from coupling into the high-band receive circuit, maintaining isolation characteristics even in a compact form factor.
Solution Approach 2:
Different regions of the substrate are assigned different functions: the low-band region contains the low-band amplifier and its dedicated ground pattern, while the high-band region contains the high-band receive circuit and its dedicated ground pattern. This local differentiation ensures that each band has optimized isolation properties without requiring large overall module size.
2Ease of manufacture
If ground patterns are used for matching circuits, then electrical connection is simplified, but harmonic component leakage increases
Solution Approach 1:
Separate ground patterns are provided for the low-band amplifier and high-band receive circuit. The matching circuit of the low-band amplifier connects to its own dedicated ground pattern rather than sharing the high-band ground pattern, preventing harmonic components from leaking through the ground connection into the high-band receive circuit.
3Productivity
If device size is reduced, then integration density increases, but electromagnetic and electrostatic coupling between circuits increases
Solution Approach 1:
The module is segmented into spatially separated low-band and high-band regions. The low-band amplifier circuit and its associated matching circuit are positioned in a low-band region, while the high-band receive circuit is positioned in a high-band region. This spatial segmentation reduces electromagnetic and electrostatic coupling between the circuits despite the compact overall size.
Solution Approach 2:
A separator circuit is positioned between the low-band amplifier and high-band receive circuit to act as an intermediary that blocks coupling paths. The separator prevents direct electromagnetic and electrostatic interaction between the two circuits, enabling high integration density without excessive coupling interference.
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 effectively reduces or prevents harmonic component leakage from low-band to high-band signals, enhancing isolation characteristics and allowing for efficient simultaneous transmission and reception of signals across different frequency bands.
Implementation Method 1
a first separator circuit that causes a transmitting signal in the first band amplified by the first amplifier circuit to pass through the first separator circuit and transmits the transmitting signal to the first antenna terminal and that causes a received signal in the first band input from the first antenna terminal to pass through the first separator circuit
Implementation Method 2
electromagnetic coupling and electrostatic coupling (hereinafter simply referred to as coupling) may occur between devices or between transmission lines
Implementation Method 3
electromagnetic coupling and electrostatic coupling (hereinafter simply referred to as coupling) may occur between devices or between transmission lines
Data Source
AI summary
A radio-frequency module includes a first transmitter-and-receiver that transmits and receives a signal in a first band, and a second transmitter-and-receiver that transmits and receives a signal in a second band higher than the first band. The first transmitter-and-receiver includes a first amplifier circuit and a first separator circuit and the second transmitter-and-receiver includes a second amplifier circuit and a second separator circuit. The first separator is located on a substrate between the first amplifier circuit and the second separator circuit, such that the first separator circuit is spatially interposed between the first amplifier circuit and the second separator circuit.