Monolithic Duplexer Layout With Integrated Phase Shifter
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Solution Overview
Problem
Existing duplexer designs for FDD communication systems are bulky and suffer from signal interference due to separate components and wire bonding, which is unsuitable for small-sized, high-performance devices like mobile phones.
Innovation Solution
A monolithic duplexer is fabricated with transmitting and receiving filters formed on a single substrate, integrated with a phase shifter on a packaging substrate to prevent signal interference, using a 90-degree phase difference LC parallel circuit and connection electrodes to reduce size and signal loss.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If separate elements (filters and phase shifter) are formed, packaged and combined using wire bonding method, then the duplexer can be fabricated with conventional processes, but the size becomes larger and signal loss occurs due to parasitic components
Solution Approach 1:
The patent merges the filters and phase shifter onto a single substrate, eliminating the need for separate packaging and wire bonding. This integration directly reduces the overall volume while maintaining manufacturability through conventional semiconductor fabrication processes.
Solution Approach 2:
The phase shifter is positioned within the same package structure as the filters, with connection electrodes extending through the substrate to establish direct electrical connections. This nested arrangement minimizes spatial requirements and eliminates external wire bonding.
2Ease of manufacture
If separate elements are connected by wire bonding method, then the fabrication process is simplified, but signal loss occurs due to parasitic components in wire parts
Solution Approach 1:
The patent extracts and eliminates the wire bonding connection method entirely by providing direct integrated connections between the phase shifter and filters through connection electrodes formed on the substrate, thereby removing the source of parasitic components and signal loss.
Solution Approach 2:
Connection electrodes serve as integrated intermediaries that provide direct electrical pathways between the phase shifter and filters without requiring external wire bonding, thus eliminating parasitic inductance and resistance associated with traditional wire connections.
3Volume of moving object
If filters and phase shifter are integrated on a single substrate, then the duplexer size is reduced, but the design and fabrication complexity increases
Solution Approach 1:
The substrate serves multiple functions simultaneously: it supports the filters, accommodates the phase shifter, provides connection electrodes for electrical interconnections, and acts as the final package structure. This multi-functionality reduces overall complexity despite integration.
Solution Approach 2:
The integrated design is divided into distinct functional regions on the substrate: filter regions, phase shifter region, and connection electrode pathways. This segmentation allows each component to be designed and fabricated independently using standard processes while achieving overall integration.
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
The solution results in a compact duplexer with reduced signal interference and loss, suitable for small-sized high-performance applications by integrating filters and phase shifters on a single substrate, eliminating the need for wire bonding.
Implementation Method 1
The phase shifter is typically implemented by a combination of a capacitor and an inductor that generates a frequency phase difference between the transmitted signal and the received signal of 90 degrees
Implementation Method 2
The FBAR has a high quality factor Q that is the main characteristic of the filter
Data Source
AI summary
A subminiature, high-performance monolithic duplexer is disclosed. The monolithic duplexer includes a substrate, a transmitting-end filter formed in a first area on an upper surface of the substrate, a receiving-end filter formed in a second area on the upper surface of the substrate, a packaging substrate, bonded on an area on the upper surface of the substrate, for packaging the transmitting-end filter and the receiving-end filter in a sealed state, and a phase shifter, formed on one surface of the packaging substrate and connected to the transmitting-end filter and the receiving-end filter, respectively, for intercepting a signal inflow between the transmitting-end filter and the receiving-end filter.