Dual‐band ridged tapered waveguide slot array antenna with cross‐polarisation reduction

Abstract

A novel dual‐band waveguide slot array antenna with low cross‐polarisation is proposed. The main structure of the proposed antenna consists of two waveguides in which the top broad wall of the smaller waveguide, a WR‐28 Ka‐band waveguide, is connected to the top broad wall of the larger waveguide, a WR‐90 X‐band waveguide. The WR‐28 waveguide operating in the higher frequency band of the proposed antenna acts as a ridge inside the WR‐90 waveguide operating in the lower frequency band. For achieving a suitable side lobe level (SLL) and cross‐polarisation in the lower frequency band, the slots are placed close to the higher frequency waveguide and side ridges are placed beside each slot. A 2D graph is presented in which the normalised resonance conductance versus the offset of a side ridge from the outer edge of the lower frequency waveguide is shown, while the slot is located between the higher frequency waveguide and the side ridge. By applying proper coefficients to this graph, appropriate offsets from the outer edge of the lower frequency waveguide for the side ridges are obtained so that a low SLL can be realised.

Loss mechanism of the SISL and the experimental verifications

“…The transmission line is the fundamental component of the RF and millimetre wave circuit and system. The commonly used transmission lines contain microstripe [1], coplanar waveguide (CPW) [2], stripline [3], metallic waveguide [4], substrate integrated waveguide [5], and so on. Recently, a new platform named substrate integrated suspended line (SISL) [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] has been proposed, and it features good properties like low loss, selfpackaging, low cost, and high integration.…”

Horn array antenna with high aperture efficiency and suppressed grating lobes

“…Slot arrays with corporate feeding network can introduce high efficiency, but they suffer from quite hard design and complex manufacturing process when a large array with high gain is required [6][7][8]. Waveguide slot arrays are efficient antennas with a simple feeding network; however, they introduce quite low operating bandwidth [9][10][11][12][13][14][15]. The array with horn elements can be considered as a solution to design a high gain flat antenna with a quite simpler feeding network compared to the same size slot array counterpart.…”