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The design, development and characterisation of an inclined waveguide slot-based circularly polarised (CP) omnidirectional antenna at Ka-band frequency are described. The antenna consists of inclined slots on a circular waveguide and a coaxial feeding probe. All the radiating slots are fed by the TM 01 mode of the circular waveguide to generate the omnidirectional pattern. Inclination of slots has been used to generate circular polarisation. The designed antenna has omni coverage in the azimuthal plane and −10°to +45°coverage in the elevation plane. The antenna has been simulated on finite element method-based ANSYS high-frequency structure simulator (HFSS) EM simulator software using proper boundary conditions. The proposed antenna has the advantages of being robust, having wide coverage, being easy to fabricate (being in waveguide configuration) and is suitable for mass production. The measured axial ratio lies well below 2.8 over the horizontal plane. A voltage standing wave ratio of 2.0:1 has been achieved over the frequency band of 37.9-38.55 GHz and the minimum omni gain of the antenna is 0 dBi over the frequency band as well as over the coverage.

Abstract-Present paper describes the design, development and evaluation of a wideband, compact Ku-band orthomode transducer (OMT) for SATCOM application. It consists of a square waveguide output section, square waveguide to rectangular waveguide transition, straight waveguide port and an orthogonally coupled port. A tapered waveguide section has been used to couple the orthogonal RF (Radio Frequency) signal to the common port. The designed OMT has a transmit port with frequency band 13.75 GHz-14.5 GHz and a receive port with frequency band 10.95-12.5 GHz. Finite element method based ANSYS's High Frequency Structure Simulator (HFSS) EM software has been used for simulation and optimization of OMT. Measured reflection coefficients of OMT over transmission and reception frequency bands are better than −15 dB and −12 dB, respectively. Designed OMT has port to port isolation better than 45 dB against 30 dB isolation of conventional OMT available in market.

The paper describes the design and development of a low profile wide scanned conformal active 1 × 32 phased array antenna for Ku-band SATCOM applications. The realized antenna is diagonally polarized and covers full transmit frequency band (i.e. 13.75–14.5 GHz) of Ku band SATCOM. All the developed sub-systems of the antenna, i.e. conformal radiating array, conformal transmit module, manifold network, and beam steering unit are described. The VSWR of the antenna is better than 1.65 over the complete transmit frequency band. The antenna has the beam steering capability of ±60° in the array plane. Designed antenna is best suited for airborne applications, where antenna profile contributes considerable aero drag and RCS to the host platform.

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