Non-Reciprocal Circuit Element for Multiband Isolation
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Solution Overview
Problem
Existing non-reciprocal circuit elements, such as isolators, face challenges in providing wideband isolation characteristics, making them inadequate for modern mobile communication systems that require handling multiple frequency bands, and they are not suitable for use in both transmission and reception circuit units due to size constraints.
Innovation Solution
A non-reciprocal circuit element is designed with a ferrite and permanent magnet configuration, incorporating a filter that provides wideband forward transmission with low loss and wideband reverse attenuation, allowing it to be used in both transmission and reception circuit units by reducing reverse transmission waves through a resistor and filter combination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If isolator is used for both transmission and reception circuit units, then device size is reduced, but isolation performance deteriorates due to size constraints
Solution Approach 1:
The non-reciprocal circuit element is designed with multi-functionality to serve both transmission and reception circuit units. By integrating forward transmission enhancement (L1, C1, L2, C2) and reverse attenuation (filter F1, resistor R1) in a single compact configuration, the device achieves universal applicability without compromising isolation performance, resolving the contradiction between size reduction and performance maintenance.
2Device complexity
If conventional isolator configuration is used, then circuit simplicity is maintained, but adaptability to multiband communication deteriorates
Solution Approach 1:
The filter F1 is designed with specific frequency characteristics that enable it to handle multiple frequency bands. By changing the filter's frequency response parameters, the circuit maintains adaptability to multiband communication while preserving relative simplicity in the overall configuration. The resistor R1 provides broadband damping that complements the frequency-selective filter.
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 achieves improved isolation characteristics over a wide band, enabling the non-reciprocal circuit element to be used in multiband transmission and reception units, reducing the size of the transmission and reception module and stabilizing power amplifier operations by preventing reverse power transmission.
Implementation Method 1
a ferrite 32 to which a direct current magnetic field is applied by a permanent magnet 41
Implementation Method 2
a ferrite 32 to which a direct current magnetic field is applied by a permanent magnet 41
Data Source
AI summary
A non-reciprocal circuit element includes a ferrite to which a direct current magnetic field is applied by a permanent magnet, and first and second center electrodes arranged on the ferrite so as to intersect with and be insulated from each other. One end of the first center electrode is connected to a first port and the other is connected to a second port. One end of the second center electrode is connected to the second port and the other is connected to a ground port. A first capacitor and a resistor connected in parallel are connected between the first and second ports and a second capacitor is connected between the second and ground ports. An input/output terminal of at least one filter is connected between the first or second port and the resistor and the ground terminal thereof is connected to the second or first port.