Balanced Antenna System for MIMO Isolation and Size
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Solution Overview
Problem
Current portable devices face challenges in implementing multiple-input-multiple-output (MIMO) wireless systems due to the complexity of housing multiple antennas in a small space while maintaining frequency coverage across various frequency ranges, particularly at lower frequencies like DVB-H, GSM, or UMTS, where balanced antenna systems are difficult to design effectively.
Innovation Solution
A balanced antenna system is designed with a radiator connected via a matching circuit to a balun, allowing for a wide tuning range and flexibility, incorporating two identical external matching circuits and a wideband LC balun to convert unbalanced signals to balanced signals, enabling operation across a broad frequency spectrum without requiring additional spectrum or transmitter power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple antennas are gathered in a small portable device, then MIMO wireless system capability is achieved, but maintaining required isolation between each radiator becomes difficult
Solution Approach 1:
The patent divides the antenna system into multiple independent radiating elements (first and second radiating elements) with separate feed lines and matching circuits. Each element can be independently controlled and tuned, allowing MIMO functionality while maintaining isolation through separate impedance matching networks that prevent coupling between elements.
Solution Approach 2:
The patent introduces matching circuits as intermediary components between the feed lines and radiating elements. These matching circuits act as mediators that isolate the radiating elements from each other while enabling proper impedance matching, thus achieving both MIMO capability and required isolation in a compact form.
2Adaptability or versatility
If balanced antenna systems are designed for lower frequencies (DVB-H, GSM, UMTS), then frequency coverage is improved, but physical size of resonance becomes too large for portable devices
Solution Approach 1:
The patent employs compact radiating element designs that nest the antenna structure within the limited space of portable devices. The feed lines and matching circuits are integrated in a nested arrangement that allows lower frequency operation without proportionally increasing the overall device volume, enabling DVB-H, GSM, and UMTS coverage in compact form.
Solution Approach 2:
The patent utilizes three-dimensional space arrangement of the radiating elements and feed lines to achieve lower frequency resonance without increasing the two-dimensional footprint. By optimizing the spatial configuration and using vertical stacking where applicable, the antenna system fits portable device constraints while covering lower frequency bands.
3Ease of manufacture
If a simple balanced antenna structure is used, then ease of manufacture is improved, but tuning capacity and flexibility are reduced
Solution Approach 1:
The patent incorporates variable matching circuits with adjustable components that allow dynamic tuning of the antenna system. The matching circuits can be adjusted to optimize performance across different frequency bands and operating conditions, providing high tuning capacity while maintaining a relatively simple overall structure that is easy to manufacture.
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 provides a compact, reconfigurable balanced antenna system capable of operating from 470 MHz to 2200 MHz with significant return loss, suitable for MIMO applications in mobile devices, offering improved signal quality and reliability across multiple frequency bands.
Implementation Method 1
a balun (which is configured to convert a single unbalanced signal into two differential balanced signals or vice versa)
Implementation Method 2
a radiator connected via a matching circuit to a balun
Implementation Method 3
a radiating element which is fed by a balanced line
Implementation Method 4
The radiator may be configured to provide a single resonant frequency or it may be configured to provide two, three of more resonant frequencies simultaneously
Data Source
AI summary
The invention relates to a balanced antenna system comprising a radiator connected via a matching circuit to a balun. In certain embodiments, the radiator comprises a first radiating element and a second radiating element and the matching circuit comprises a first impedance-matching circuit connected to the first radiating element and a second impedance-matching circuit connected to the second radiating element. The first and second matching circuits may be identical and are connected through the balun to a single port. To minimize the component count, the design of the matching circuit and balun is co-optimized.