Low-Profile Filtering Antenna with Open Stubs and Spaced Slots
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Solution Overview
Problem
Current wireless communication systems face challenges in integrating antennas and filters effectively, leading to increased module size and performance issues due to mismatched bandwidths and high losses, especially in broadband designs with multi-order resonators.
Innovation Solution
A low-profile broadband high-gain filtering antenna design incorporating a radiator, dielectric substrates, microstrip feed-lines with open stubs, a ground plane with spaced slots, and metallized vias, which allows for broadband and high-gain radiation while controlling roll-off rates and suppressing resonances without a complex filtering circuit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the antenna and filter are individually designed and cascaded, then the filtering performance is improved, but the module size increases
Solution Approach 1:
The patent merges the antenna and filter into a single integrated structure where the antenna elements serve dual functions as both radiating elements and filtering resonators. This combination eliminates the need for separate filter components and their associated 50-ohm matching ports, thereby reducing module size while maintaining filtering performance through the inherent resonant characteristics of the antenna structure.
2Area of stationary object
If co-design of filter and antenna is used, then the module size is reduced, but the filter loss increases especially in broadband design
Solution Approach 1:
The patent extracts the filtering function from the traditional filter structure and embeds it directly into the antenna elements themselves. By designing the antenna elements with specific geometric configurations that create resonant frequencies corresponding to the desired filter passband, the structure achieves filtering without requiring separate filter components, thereby reducing the energy loss associated with multiple matching interfaces and cascaded structures.
3Adaptability or versatility
If multi-order resonator is used for broadband design, then the bandwidth is improved, but the loss becomes more severe
Solution Approach 1:
The patent segments the broadband filtering function across multiple antenna elements, each contributing to different frequency ranges. By arranging multiple antenna elements with varying dimensions and configurations, the structure achieves broadband coverage through cumulative effect rather than relying on a single high-order resonator, thereby reducing the loss that would otherwise be incurred by complex high-order filtering structures.
4Ease of operation
If standard 50 ohm matching ports are used, then the impedance matching is improved, but the loss increases
Solution Approach 1:
The patent makes the antenna elements universal by designing them to simultaneously serve as radiating elements, filtering resonators, and impedance-matching structures. The same geometric features that define the resonant frequencies for filtering also provide the necessary impedance transformation, eliminating the need for separate matching networks and their associated loss.
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 high impedance bandwidth, low loss, and effective harmonic suppression with a compact structure, maintaining good filtering performance across various bandwidths and reducing the complexity of filtering circuits.
Implementation Method 1
the radiator generates resonances and provides a broadband and high-gain radiation passband
Implementation Method 2
the open stub generates a radiation null, and suppresses a resonance of the antenna in upper band
Implementation Method 3
the spaced slots suppresses a resonance of the antenna in lower band
Implementation Method 4
the metallized via connects the microstrip feed-line and the ground plane, generates a radiation null, and improves the roll-off rate
Data Source
AI summary
The present invention discloses a low-profile broadband high-gain filtering antenna. The antenna comprises a radiator, an upper-layer dielectric substrate, a lower-layer dielectric substrate, a microstrip feed-line having open stubs, a ground plane having a plurality of spaced slots, and a metallized via. The radiator generates resonances, provides a broadband and high-gain radiation passband, and meanwhile, adjusting the dimensions of the radiator can adjust the roll-off rate at the upper edge of the passband. The open stub generates a radiation null, and suppresses a resonance in upper band of the antenna. The spaced slot suppresses a resonance in lower band of the antenna. The metallized via connects the microstrip feed-line and the ground plane, generates a radiation null, and improves the roll-off rate at the lower edge of the passband.