Opportunity
The rapid advancement of intelligent transportation systems and vehicle-to-everything (V2X) communications demands reliable, real-time wireless connectivity between vehicles and infrastructure. A critical component enabling this is the antenna, which must possess agile beam-steering capability to maintain stable links as relative positions between vehicles and devices change dynamically. Conventional phased array antennas, while offering beam steering, suffer from a limited scanning range due to significant gain loss at large angles. This limitation stems from strong mutual coupling between antenna elements and the inherently narrow beamwidth of individual element radiation patterns. Existing solutions to achieve broad-beam antenna elements, such as using multiple resonant modes, adding metallic strips or magnetic currents, or employing dielectric resonator antennas, often result in high-profile designs unsuitable for vehicular applications where low wind resistance is essential. Other approaches utilizing reconfigurable patterns with PIN diodes or multi-port designs increase complexity and cost. While low-profile designs using high-impedance surfaces or artificial magnetic conductors exist, they typically require multi-layer printed circuit boards, raising manufacturing expenses and complexity. Therefore, a significant market and technical opportunity exists for developing a low-cost, low-profile phased array antenna that maintains a wide beam-steering range, specifically tailored for the stringent demands of modern vehicular communication systems.
Technology
The present invention addresses the aforementioned challenges by introducing a novel multi-slot antenna element and a phased array constructed therefrom. The core innovation lies in a single-substrate, multi-slot antenna design that generates a hybrid magnetic current to achieve an exceptionally wide H-plane beamwidth. The antenna comprises a ground plane with a central driven slot extending along a first direction (e.g., y-direction). It is flanked by four L-shaped parasitic slots—two on each side—symmetrically arranged about the driven slot. Each L-shaped slot extends along both the first and a second, orthogonal direction (e.g., x-direction). This specific configuration allows the antenna to be modeled as a combination of two types of equivalent magnetic currents: a y-directed magnetic current (MC1) originating from the central driven slot, which provides a broadside radiation pattern, and four x-directed magnetic currents (MC2) from the parasitic slots, which enhance low-elevation, end-fire radiation. By carefully designing the dimensions, particularly the length of the short arm (L_s3) of the L-shaped parasitic slots, the weighting coefficient (A) between MC1 and MC2 can be flexibly tuned. This enables the superposition of complementary radiation patterns (broadside and end-fire) to synthesize a very wide, flexible H-plane beam with minimal gain fluctuation (e.g., less than 1 dB ripple). The element achieves a measured 3-dB beamwidth of 217°. This wide-beam element is then used as the building block for a linear phased array. The elements are continuously arranged on a single shared substrate with a compact inter-element spacing (e.g., 0.46λ₀), forming a low-profile array. The array leverages the wide beamwidth of each element to enable a remarkable beam-steering range from -90° to +90° in the H-plane, overcoming the scanning limitations of conventional arrays.
Advantages
- Achieves an exceptionally wide H-plane beam-steering range from -90° to +90°.
- Features a very low physical profile, ideal for vehicular mounting to minimize wind resistance.
- Utilizes a simple, single-substrate printed circuit board (PCB) structure, reducing manufacturing cost and complexity compared to multi-layer designs.
- The wide-beam antenna element allows for a compact inter-element spacing in the array, helping to avoid grating lobes.
- Provides flexible beam shaping by tuning the L-shaped parasitic slot dimensions to control the radiation pattern.
- Demonstrates competitive performance with moderate gain fluctuation (e.g., 2.1 dB measured) across the full scanning range.
- Offers good impedance matching and isolation between array elements.
Applications
- Vehicle-to-Everything (V2X) communication systems, including vehicle-to-vehicle (V2V), vehicle-to-infrastructure (V2I), and vehicle-to-network (V2N) links.
- Advanced driver-assistance systems (ADAS) and autonomous vehicle sensing and communication.
- Radar systems requiring wide-angle scanning capabilities.
- Satellite communication terminals on mobile platforms.
- Mobile telecommunication base stations or user equipment requiring agile beam steering.
