Opportunity
The rapid advancement of wireless communication systems, particularly in applications like global positioning systems (GPS), has highlighted the need for antennas capable of operating across multiple frequency bands simultaneously. Traditional antennas often struggle to cover multiple bands efficiently, requiring separate units for each frequency, which increases system complexity, size, and cost. For instance, GPS applications commonly use L1 (1.575 GHz) and L2 (1.227 GHz) bands, but existing solutions like quadrifilar helix antennas (QHAs) or planar cross-dipole antennas face limitations. QHAs are difficult to fabricate due to their intricate curl arms and are sensitive to manufacturing tolerances, while planar cross-dipole antennas often fail to provide sufficient axial ratio (AR) beamwidths to cover the upper hemisphere, which is critical for receiving low-elevation satellite signals. These shortcomings create a demand for a compact, multi-band antenna with wide AR beamwidths and simplified feed networks to enhance performance in GPS and other multi-band wireless systems.
Technology
The patent addresses these challenges by introducing a multi-band antenna featuring a novel combination of curved cross-dipole arms and a corrugated back cavity structure. The antenna comprises multiple dipole antennas, each optimized for a distinct frequency band (e.g., L1 and L2 for GPS), integrated into a single structure. The dipole arms are designed with unequal lengths and subtended angles to resonate at different frequencies, while their curved shape broadens the AR beamwidth. The back cavity structure is corrugated to further enhance beamwidth, achieving coverage exceeding 200°—enough to span the upper hemisphere. A two-stage cascaded hybrid coupler serves as the feed network, simplifying the excitation of circularly polarized signals across bands. The antenna substrates are orthogonally arranged and partially housed within the cavity, reducing footprint and improving mechanical stability. This design eliminates the need for multiple antennas, offering a compact, high-performance solution for multi-band applications.
Advantages
- Multi-band operation: Supports simultaneous communication in distinct frequency bands (e.g., GPS L1 and L2).
- Wide AR beamwidth: Exceeds 200°, enabling full upper-hemisphere coverage for low-elevation signal reception.
- Compact integration: Combines multiple dipoles into a single structure, reducing system complexity and size.
- Circular polarization: Minimizes multipath interference and orientation sensitivity.
- Corrugated cavity: Enhances beamwidth without increasing antenna profile.
- Simplified feed network: Cascaded hybrid coupler ensures efficient signal distribution across bands.
Applications
- GPS systems: Ground terminals, vehicular navigation, and maritime tracking.
- Satellite communication: Low-earth orbit (LEO) and geostationary satellite links.
- Military and aerospace: Robust multi-band communication in dynamic environments.
- 5G and IoT: Multi-frequency support for emerging wireless standards.
- Avionics: Aircraft navigation and telemetry systems.
