High-Gain Conical-Beam Traveling-Wave Array Antenna Based on a Slotted Circular Waveguide at $Ku$ -Band

A high-gain conical-beam traveling-wave array antenna based on a slotted circular waveguide is designed at the higher part of Ku-band. A single radiating element is formed by a ring of eight equally spaced slots fed by a circular waveguide. The excitation of the nonfundamental TM01 mode provides a uniform feeding distribution to each slot, generating an omnidirectional radiation performance. Thus, an array antenna formed by 48 rings of slots is proposed following the design rules of traveling-wave arrays. Every ring is properly designed to achieve a uniform power distribution and consequently maximum directivity for the array antenna performance. The distance between elements is also adjusted to obtain the better input matching response and mitigate the grating lobe appearance, generating a high-gain conical-beam radiation performance suitable for satellite and fifth-generation communications. The proposed antenna design has been manufactured in plastic material by using a 3-D printing process and plated by a spray metallization process. A -10 dB impedance bandwidth higher than 23%, high-gain values around 13.5 dB, or total efficiency higher than 98% has been achieved for the whole frequency band.