Crossed Dipole Antenna with Capacitive Feed for Multi-Band Interference
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Multi-band antennas face challenges in minimizing interference and distortion between radiating elements operating at different frequency bands, particularly due to common and differential mode resonances, which affect radiation patterns and increase complexity and cost.
Innovation Solution
A dipole antenna design featuring a crossed dipole arrangement with capacitively coupled conductive transmission lines and a hybrid feeding mechanism, including a non-contacting reactive-coupled feed element, which reduces interaction between low-band and high-band radiating elements, providing stable radiation patterns and minimizing back emissions and cross-polarization emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple radiating elements with different operating frequencies are implemented in multi-band antennas, then the antenna can support multiple frequency bands (GSM900, GSM1800, UMTS, LTE), but radiation patterns for lower frequency bands are distorted by resonances in higher frequency band radiating elements
Solution Approach 1:
The patent extracts and removes the harmful resonant effects from the system by introducing compensating radiating elements that generate opposite-phase resonances to cancel out the disturbing resonances from higher band elements, thereby preserving the radiation pattern stability of lower band operations
Solution Approach 2:
The patent applies preliminary anti-action by pre-configuring compensating radiating elements with specific dimensions and orientations that produce resonances in advance to counteract and neutralize the harmful resonances that would otherwise occur during multi-band operation
2Productivity
If radiating elements dimensioned for one band are used, then the antenna operates efficiently at that band's frequency, but the same elements cause interference and distortion when higher band elements are added to the antenna
Solution Approach 1:
The patent converts the harmful resonant effects generated by higher band radiating elements into beneficial counter-resonances by strategically designing compensating elements that produce opposite-phase resonances, thereby transforming interference into a mechanism that protects lower band radiation patterns
Solution Approach 2:
The patent creates a composite radiating structure that combines multiple types of radiating elements (half-wave dipoles, quarter-wave monopoles, and compensating elements) with different dimensional characteristics to achieve both efficient multi-band operation and reduced inter-band interference
3Stability of the object's composition
If common mode resonance occurs in higher band radiating structures, then the structure resonates as a quarter wave monopole at lower band frequencies, but this causes distortion in the lower band radiation pattern
Solution Approach 1:
The patent introduces compensating radiating elements as intermediary structures that mediate between the higher band radiating elements and the lower band operating environment, absorbing and redirecting the harmful common mode resonances away from the lower band radiation patterns
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 design achieves ultra-wide bandwidth performance across 554-960 MHz with reduced interference, maintaining consistent beam shape and gain across the frequency range, while lowering manufacturing costs and complexity.
Implementation Method 1
The feed element includes first and second conductive transmission lines that are electrically isolated from one another and are capacitively coupled to the arm segments of the first and second dipoles, respectively
Implementation Method 2
The first and second dipoles respectively include arm segments and are arranged in a crossed dipole arrangement
Implementation Method 3
Common Mode (CM) resonance can occur when the entire higher band radiating structure resonates as if it were a one quarter wave monopole
Data Source
AI summary
A dipole antenna includes a reflector, a radiating element, and a feed element. The radiating element includes first and second dipoles above a surface of the reflector. The first and second dipoles respectively include arm segments and are arranged in a crossed dipole arrangement. The feed element includes first and second conductive transmission lines that are electrically isolated from one another and are capacitively coupled to the arm segments of the first and second dipoles, respectively. The arm segments of the first and second dipoles are between the feed element and the surface of the reflector.