Omnidirectional PCB Antenna with Amplitude Taper for Sidelobe Suppression
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Solution Overview
Problem
Conventional antennas do not adequately suppress radiation in ≥30° skyward regions to at most −15 dB below the peak gain, are not omnidirectional in the azimuth plane, and lack sufficient operational bandwidth, failing to meet FCC regulations for EIRP limits and broadband requirements.
Innovation Solution
A horizontally-polarized omnidirectional antenna with broadband amplitude taper, featuring a design with a host PCB, metal-flooded ground plane, and loop antenna elements, which includes a multi-section transformer and capacitive elements to achieve high sidelobe suppression and omnidirectional coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If conventional antenna designs are used, then the antenna structure is simple, but the sidelobe suppression is insufficient and EIRP limits cannot be met
Solution Approach 1:
The antenna elements are arranged in a segmented circular array configuration, dividing the radiation pattern control into multiple discrete elements that can be individually tapered. This segmentation enables precise control of sidelobe levels while maintaining a manageable structural complexity through systematic element placement.
Solution Approach 2:
Different amplitude tapering is applied to different antenna elements based on their position in the circular array. Elements are fed with varying amplitudes to create a non-uniform excitation pattern that specifically targets sidelobe suppression in certain directions while maintaining main lobe performance, achieving local optimization of radiation characteristics.
2Adaptability or versatility
If conventional antenna designs are used, then the manufacturing process is simple, but omnidirectional coverage and broadband performance cannot be achieved
Solution Approach 1:
The circular array of antenna elements provides universal omnidirectional coverage in the azimuth plane, allowing the antenna to function effectively in all horizontal directions. This multi-directional capability is achieved through the symmetric geometric arrangement and uniform phase distribution across the circular aperture.
Solution Approach 2:
The antenna transitions from a planar two-dimensional structure to a three-dimensional circular array configuration. By arranging elements in a circle rather than a flat grid, the design achieves omnidirectional coverage while maintaining a compact form factor, adding a rotational dimension to the element distribution.
3Adaptability or versatility
If conventional antenna designs are used, then the bandwidth is limited, but the antenna can be designed for specific frequency bands
Solution Approach 1:
The feed network incorporates variable impedance transformation ratios and adjustable phase shifters that can be tuned across different frequency bands. By changing the electrical parameters of the feeding elements and transmission lines, the antenna maintains broadband operation while adapting to different operational requirements.
Solution Approach 2:
The antenna system employs dynamically adjustable feed networks with variable amplitude and phase control for each element. This dynamic capability allows the antenna to adapt its radiation pattern and impedance matching across a wide frequency range, achieving broadband performance through real-time parameter adjustment.
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 antenna provides high sidelobe suppression, meeting EIRP limits and ensuring omnidirectional performance across a wide bandwidth, enhancing system-level performance with increased range and data rates.
Implementation Method 1
ends of each of the second plurality of conducting strips slightly overlap ends of each of the first plurality of conducting strips to form a plurality of capacitive elements at overlap regions
Implementation Method 2
A horizontally-polarized omnidirectional antenna with broadband amplitude taper... provides high sidelobe suppression and thereby improves system-level performance
Data Source
AI summary
A horizontally-polarized omnidirectional antenna, including: a body including: a host printed circuit board (PCB) including: a metal-flooded ground plane, windows, and an interconnect providing a radio frequency (RF) signal splitting off into 2*Z0 transmission lines, a plurality of antenna elements, corresponding to respective windows, including: an antenna PCB including an antenna slot having a pullback region with the host PCB therein without directly contacting the pullback region, the window in the antenna slot, loops of conducting strips at top and bottom sides of the antenna PCB, slightly overlapping to form capacitive elements at overlap regions, a pair of input solder joints at respective input conducting strips on the top of the antenna PCB, on opposite sides of the window, a transmission feed solder joint directly between the pair of input solder joints across the window, connected to a Z0 feed line, and an RF connector receiving an antenna power supply.