Tunable Multiband Antenna With Passive Filter And Inductor
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Solution Overview
Problem
Incorporating antennas and other electrical components into electronic devices with small form factors is challenging due to limited space and the influence of conductive structures on component performance, particularly in wireless communication devices.
Innovation Solution
The use of patterned metal structures on a dielectric carrier, such as a plastic carrier, to form antenna structures that include an inverted-F antenna resonating element and a tunable inductor to achieve coverage in both low and high frequency communications bands, with a passive filter creating a short circuit impedance to enhance high band resonance and adjustable components for tuning low band resonance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional antennas and electrical components are incorporated into electronic devices with small form factors, then wireless communication functionality is achieved, but space is limited and conductive structures influence component performance
Solution Approach 1:
The patent combines the antenna structure with the printed circuit board by integrating the resonating element as a trace on the PCB. This merging eliminates the need for separate antenna components and reduces overall space requirements while maintaining wireless communication functionality.
Solution Approach 2:
The antenna structure serves multiple functions: it provides wireless communication capability, acts as a signal transmission path, and utilizes the PCB ground plane as its reference. This multi-functionality reduces the number of separate components needed and optimizes space utilization.
2Adaptability or versatility
If conductive structures are added to enable antenna functionality, then wireless communication bands are covered, but the performance of electronic components is influenced and space is restricted
Solution Approach 1:
The patent implements frequency-selective filtering at specific locations along the antenna trace using localized RC circuits. This allows different portions of the antenna to handle different frequency bands independently, improving performance reliability without requiring complete redesign of the entire antenna structure.
Solution Approach 2:
The patent introduces RC filtering circuits as intermediary elements between the antenna trace and ground. These circuits act as mediators that selectively filter frequencies, allowing the antenna to cover multiple bands while preventing interference between different frequency ranges and maintaining component performance.
3Reliability
If a passive filter is coupled between portions of the low band arm to create short circuit impedance at high band frequencies, then high band resonance is enhanced, but device complexity increases
Solution Approach 1:
The patent uses RC circuits with specific resistance and capacitance values to create frequency-dependent impedance characteristics. By carefully selecting component values, the filter presents a short circuit at high band frequencies to enhance resonance while appearing as an open circuit at low band frequencies, allowing single-component solutions for complex filtering requirements.
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 configuration allows for efficient coverage of wireless communications bands while minimizing space constraints, enabling effective antenna performance in compact electronic devices.
Implementation Method 1
A passive filter that is coupled between first and second portions of the low band arm in the antenna resonating element may be configured to exhibit a short circuit impedance at frequencies associated with a second high band resonance in the high band
Implementation Method 2
The tunable component may be a tunable inductor that is actively tuned during operation of the antenna and electronic device
Implementation Method 3
The antenna resonating element may have a high band arm that contributes to a first high band resonance in the high band and may have a low band arm that gives rise to a low band resonance in the low band
Data Source
AI summary
An electronic device may have an antenna for providing coverage in wireless communications bands of interest such as a low frequency communications band and a high frequency communications band. The antenna may have an antenna ground and an antenna resonating element. The antenna resonating element may have a high band arm that contributes to a first high band resonance in the high band and may have a low band arm that exhibits a low band resonance in the low band. A passive filter that is coupled between first and second portions of the antenna resonating element may be configured to exhibit a short circuit impedance associated with a bypass path that allows the antenna resonating element to contribute to a second high band resonance in the high band. A tunable inductor coupled to the antenna resonating element may be used to tune the low band resonance.