Bent Monopole Antenna for Vehicle Fin Shell
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Solution Overview
Problem
Monopole antennas for vehicle-use communication systems face challenges in accommodating multiple frequency bands and maintaining MIMO performance due to space constraints and high mutual coupling within fin-shaped shells, especially for low-band frequencies.
Innovation Solution
The antenna device features two symmetrically protruding monopole antennas with intersecting projections on a projection plane, a gap between them, and a slot through the connection portion to adjust frequency reception, along with supporting boards and isolating bodies to reduce mutual coupling and improve isolation, allowing for dual-band operation and reduced height for accommodation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the length of monopole antenna is increased to receive low-band frequency (e.g., 700 MHz), then the frequency receiving capability is improved, but the antenna height becomes too long and cannot be accommodated within the fin-shaped shell space
Solution Approach 1:
The monopole antenna is designed with a bent structure instead of a straight configuration. The antenna includes a first section extending upward from the circuit board, a second section extending laterally from the first section, and a third section extending upward from the second section. This dimensional transformation allows the antenna to achieve the required electrical length for low-band frequency reception while maintaining a compact vertical profile that fits within the fin-shaped shell.
Solution Approach 2:
The bent monopole antenna structure is nested within the fin-shaped shell configuration. The antenna's multi-section path is arranged to fit within the limited space defined by the shell, effectively nesting the extended antenna path within the compact housing structure.
2Volume of stationary object
If two monopole antennas are placed close together in limited space, then the device compactness is improved, but the mutual coupling effect increases and MIMO performance deteriorates
Solution Approach 1:
The two monopole antennas are configured with asymmetric orientations. Each antenna has its second section extending in different lateral directions, creating non-parallel current paths. This asymmetric arrangement reduces the mutual coupling between the two antennas while maintaining compact spacing, thereby preserving MIMO performance within limited volume.
3Ease of manufacture
If the monopole antenna structure is simplified for easy manufacturing, then the manufacturing ease is improved, but the ability to accommodate multiple frequency bands and maintain MIMO performance is reduced
Solution Approach 1:
The monopole antenna is segmented into three distinct sections: a first section extending upward from the circuit board, a second section extending laterally, and a third section extending upward again. Each section can be independently optimized for its function. The segmentation allows the antenna to achieve complex multi-frequency band performance and MIMO compatibility while maintaining relative manufacturing simplicity through modular construction.
Data Source
AI summary
An antenna device is provided and includes a bottom, two monopole antennas, and a cover assembled with the bottom. A projection plane is defined perpendicular to the bottom. The two monopole antennas substantially symmetrically protrude from the bottom, and a gap is formed between the two monopole antennas. Projections of the two monopole antennas on the projection plane intersect with each other. Each of the two monopole antennas includes a first frequency receiving portion adjacent to the bottom, a second frequency receiving portion, and a connection portion located between the first frequency receiving portion and the second frequency receiving portion. A slot is formed through the connection portion to adjust a received frequency of the first or second frequency receiving portion. An accommodating space is formed between the cover and the bottom to accommodate the two monopole antennas.