Multi-band Antenna Balun for Inter-band Interference Control
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Solution Overview
Problem
In multi-band antenna systems, inter-band interference occurs when radiating elements operating at different frequency bands operate simultaneously, leading to induced currents and distorted antenna patterns due to differential mode radiation.
Innovation Solution
Incorporating a balun with conductive structures, such as short-circuit stubs and plated through holes, to divert differential mode signals to the grounding structure, preventing them from flowing into the radiation arms and reducing inter-band interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If radiating elements in different frequency bands operate simultaneously, then multi-band communication capability is achieved, but inter-band interference occurs due to differential mode radiation
Solution Approach 1:
The balun acts as an intermediary component between the feed plate and radiation arms. It transforms the differential mode signal obtained from the second radiating element into a common mode signal, preventing the signal from causing differential mode radiation in the first radiating element. This mediator function resolves the interference while maintaining multi-band operation capability
Solution Approach 2:
The invention converts the harmful differential mode signal into a beneficial common mode signal through the balun transformation. The differential mode signal that would normally cause interference is transformed into a common mode signal that does not generate differential mode radiation, thereby eliminating the harmful effect while utilizing the same signal energy
2Measurement precision
If low frequency signal is sensed by high-band radiating element, then signal reception is achieved, but induced current flows between radiation arms causing differential mode radiation
Solution Approach 1:
The balun serves as an intermediary that intercepts the low frequency differential mode signal sensed by the high-band radiating element. By transforming this signal into common mode before it can flow into the radiation arms, the balun prevents the formation of induced currents that would cause differential mode radiation, while still allowing the signal to be properly received and processed
3Productivity
If differential mode signal flows into radiation arm, then signal transmission is achieved, but antenna pattern distortion occurs
Solution Approach 1:
The balun acts as a mediator that transforms the differential mode signal into common mode signal, preventing the signal from flowing directly into the radiation arms in differential mode. This transformation maintains signal transmission efficiency while preserving the antenna radiation pattern from distortion that would occur with direct differential mode injection
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 solution effectively suppresses differential mode resonance, ensuring normal operation of both high- and low-band radiating elements, enhancing radiation gain and maintaining antenna pattern integrity.
Implementation Method 1
The balun is configured to: after obtaining a differential mode signal, transform the differential mode signal into a common mode signal
Implementation Method 2
the high-band radiating element uses the balun structure, in other words, the high-band radiating element can block backflow of the low frequency signal between the radiation arms
Implementation Method 3
after obtaining the differential mode signal, the balun can input the differential mode signal to the grounding structure by using the at least one conductive structure
Data Source
AI summary
A multi-band antenna system and a method for controlling inter-band interference in the multi-band antenna system are provided. The multi-band antenna system includes at least one first radiating element and at least one second radiating element. An operating frequency band of the first radiating element is higher than an operating frequency band of the second radiating element. Each first radiating element includes a grounding structure, a balun, and at least two radiation arms. One end of the balun is electrically connected to the at least two radiation arms. The balun includes at least one conductive structure. The balun is configured to: after obtaining a differential mode signal, input the differential mode signal to the grounding structure using the at least one conductive structure. The differential mode signal is a signal obtained by the balun by sensing a signal from the second radiating element in a differential mode manner.