Laminated RF Triplexer Circuit With FET Switching for Multi-Band Blocking
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Solution Overview
Problem
Current high-frequency circuits and triplexers struggle to efficiently handle multiple frequency bands, particularly those used in WiMAX and wireless LAN, due to size and cost constraints, and fail to provide satisfactory blocking of unwanted frequency bands, especially when frequency bands are close together.
Innovation Solution
A high-frequency circuit design incorporating a switch circuit with field-effect transistors, triplexers configured with low-pass, band-pass, and high-pass filters, and diplexers, using inductance and capacitance elements on a laminated substrate to minimize size and cost, while ensuring excellent triplexer characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a composite LC filter circuit or triplexer is used to branch signals of three different frequencies, then signal branching for multiple frequency bands is achieved, but the circuit size and cost increase
Solution Approach 1:
The triplexer is divided into three separate band-pass filters, each handling a specific frequency band (2.5 GHz, 3.5 GHz, 5.8 GHz). This segmentation allows independent optimization of each filter and simplifies the overall circuit layout on the laminated substrate, reducing total circuit size while maintaining multi-band functionality.
Solution Approach 2:
The patent transitions from planar circuit layout to three-dimensional laminated substrate construction. By stacking multiple circuit layers and using vertical interconnections, the circuit achieves compact size in the horizontal plane while maintaining the necessary filtering functions for multiple frequency bands.
2Reliability
If triplexer lines are arranged between filters to modify triplexer performance, then signal branching performance is improved, but the circuit size and manufacturing complexity increase
Solution Approach 1:
The patent combines the triplexer function directly with the band-pass filter structures. Instead of adding separate triplexer lines between filters, the filtering and signal branching functions are merged into a unified laminated substrate design, simplifying manufacturing while achieving the desired signal separation performance.
3Ease of operation
If field-effect transistors are used in the switch circuit, then switching between transmitting and receiving circuits is achieved, but noise and insertion loss increase
Solution Approach 1:
The patent optimizes the field-effect transistor parameters and circuit configuration to minimize noise and insertion loss. By carefully selecting transistor characteristics and arranging the switch circuit in specific configurations within the laminated structure, the harmful effects are reduced while maintaining effective switching capability between transmitting and receiving modes.
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 enables a compact, cost-effective high-frequency circuit capable of handling multiple frequency bands with reduced noise and insertion loss, effectively blocking unwanted frequencies and supporting multiple communication systems like WiMAX and wireless LAN.
Implementation Method 1
a switch circuit using a field-effect transistor for switching between a connection with transmitting-side circuits and a connection with receiving-side circuits
Implementation Method 2
a first triplexer that branches a transmitting path connected to the switch circuit into transmitting paths of first, second, and third frequency bands and a second triplexer that branches a receiving path connected to the switch circuit into receiving paths of the first, second, and third frequency bands
Implementation Method 3
using inductance and capacitance elements on a laminated substrate
Implementation Method 4
using inductance and capacitance elements on a laminated substrate
Data Source
AI summary
An inventive high frequency circuit includes a switch circuit (SPDT1), connected to an antenna terminal (Ant1), using a field-effect transistor for switching between a connection with first to third transmitting terminals (Tx1-1, Tx2-1, Tx3-1) and a connection with first to third receiving terminals (Rx1-1, Rx2-1, Rx3-1); a transmitting-side triplexer (Trip1) for branching a transmitting path connected to the switch circuit into transmitting paths of first to third frequency bands; and a receiving-side triplexer (Trip2) for branching a receiving path connected to the switch circuit into receiving paths of the first to third frequency bands. The switch circuit can be formed as an IC to downsize the circuit. For example, in constructing the high frequency circuit with a laminated module using a ceramic laminated substrate or the like, particularly when the number of triplexers occupying a large space is large, the switch circuit is formed as an IC and mounted on the laminated body, whereby the whole structure can be downsized.