Abstract: A dual-band dual-port antenna structure is provided. The dual-band dual-port antenna structure includes a first antenna structure and a second antenna structure. The first antenna structure operates in a high-frequency band and includes a first feeding port, a first feeding path electrically connected to the first feeding port, and a first radiating element. The second antenna structure operates in a low-frequency band and includes a second feeding port, a second feeding path electrically connected to the second feeding port, and a second radiating element. The first feeding path includes a first capacitor and a first feeding line. The second radiating element of the second antenna structure at least partially surrounds the first radiating element of the first antenna structure.

Abstract: A dual-band dual-port antenna structure is provided. The dual-band dual-port antenna structure includes a first antenna structure and a second antenna structure. The first antenna structure operates in a high-frequency band and includes a first feeding port, a first feeding path electrically connected to the first feeding port, and a first radiating element. The second antenna structure operates in a low-frequency band and includes a second feeding port, a second feeding path electrically connected to the second feeding port, and a second radiating element. The first feeding path includes a first capacitor and a first feeding line. The second radiating element of the second antenna structure at least partially surrounds the first radiating element of the first antenna structure.

Abstract: A planar helix slow-wave structure with straight edge connections where the structure consists of two arrays of thin, parallel, conductors printed on top and bottom faces of a low-loss dielectric material or substrate, the conductors in the arrays printed on the top and bottom surfaces being inclined at different but symmetric pitch angles on the surface of the planar surface, the conjunction ends of the conductors on the top and bottom faces being connected by vertical conductors with circular rings with a diameter greater than the diameter of the vertical conductors to ensure proper connections between them, and a vacuum tunnel inside the planar helix structure.

Abstract: A planar helix slow-wave structure with straight edge connections where the structure consists of two arrays of thin, parallel, conductors printed on top and bottom faces of a low-loss dielectric material or substrate, the conductors in the arrays printed on the top and bottom surfaces being inclined at different but symmetric pitch angles on the surface of the planar surface, the conjunction ends of the conductors on the top and bottom faces being connected by vertical conductors with circular rings with a diameter greater than the diameter of the vertical conductors to ensure proper connections between them, and a vacuum tunnel inside the planar helix structure.