Search Results (2)

This paper addresses the design and analytical synthesis of a corrugated horn antenna with a normalized Gaussian-type variable profile, featuring grooves of variable depth along the inner walls of the waveguide, ranging from ${\mathsf{\lambda }}_{\mathrm{X}}/4$ at the input to ${\mathsf{\lambda }}_{\mathrm{K}\mathrm{u}}/4$ at the aperture. The proposed antenna I is designed to operate simultaneously over the X-band and Ku-band (7–15 GHz), considering the frequency bands commonly employed in satellite communications. The main motivation of this study is to establish a rigorous method for determining the radius of the input waveguide rather than relying on the empirical approaches commonly used in antenna design, such as approximations from $\mathsf{\lambda }/4$ at the center frequency, which do not necessarily ensure adequate impedance matching over the entire operating bandwidth. The theoretical framework of this study is based on the analysis of modal propagation conditions in a circular waveguide, from which an analytical expression is derived for the optimum input radius of the corrugated horn antenna by simultaneously satisfying the propagation conditions associated with the fundamental hybrid HE11 mode. This approach includes a methodology for determining the minimum required length of the smooth circular-waveguide feeding section and evaluating the attenuation constant of evanescent modes below their cutoff frequencies. The geometric synthesis of the antenna profile includes the definition of the normalized Gaussian radius profile and the configuration of the corrugation, for which their depths vary linearly between the limiting values corresponding to the considered frequency bands. The analytical calculations are implemented in the MATLAB computational environment (MATLAB R2021b (MathWorks, Inc., Natick, MA, USA), while the resulting two-dimensional profile is subsequently exported through compatible files to the Ansys HFSS simulation environment (Ansys HFSS Electronics v.17.2), where the resulting three-dimensional structure is analyzed from an electromagnetic perspective. The performance of the proposed corrugated horn antenna is evaluated by comparing two approaches for determining the input radius: the empirical value r_in = $\mathsf{\lambda }/4$ = 7.5 mm and the value obtained through a rigorous minimax criterion balancing the TE₁₁ and TM₁₁ propagation conditions as a function of the waveguide cutoff frequency, r_in = 12.376 mm. The comparison is performed based on the reflection coefficient S11, the antenna gain expressed in dB, and the axial ratio in order to assess whether the proposed antenna provides the circular polarization characteristics required for satellite communication applications. The antenna’s performance is evaluated separately over the uplink and downlink frequency ranges associated with the X-band and Ku-band. The main performance requirements considered in the analysis include an axial ratio below 3 dB in the direction of maximum radiation, a gain greater than 15 dB over each frequency band of interest, and a reflection coefficient below −10 dB over at least 80% of the operating frequency range. Full article

This paper proposes a wideband profiled horn antenna designed using the piecewise biarc Hermite polynomial interpolation and validated experimentally at 55 GHz. The proposed design proves S₁₁ and directivity better than −22 dB and 25.5 dB across the entire band and only needs 3 node points if compared with the well-known spline profiled horn antenna. Our design makes use of an increasing radius and hence does not present non-accessible regions from the aperture, allowing its fabrication with electro erosion techniques especially suitable for millimeter and submillimeter wavelengths. Full article