A new $E$ -plane filtering structure suitable for very high-power telecom satellite applications is presented. The conceived configuration exploits the design flexibility provided by cascading highly integrated step/stub resonators with pseudoelliptic frequency responses. Several design examples of filters and diplexers in Ku-, K-, and Q-band are reported and supported by experimental tests campaigns. The components have been designed with a full-wave 2-D spectral element method. Prototypes have been realized in aluminum clam-shell technology. Excellent agreement between the models and the experimental results has been achieved. An alternative manufacturing of the proposed architecture based on the selective laser melting technology is also reported. The attractiveness of the structure in view of this emerging additive manufacturing solution is demonstrated. The main advantages of the proposed filter configuration suitable for components operated in heavily loaded multi-carrier environment are: compact design, very low losses, high rejection, and high power-handling capability.

The paper presents the design and validation of a dual band feed system for the reflector antenna of the CoReH2O (Cold Regions Hydrology High-resolution Observatory) SAR instrument, investigated under ESA contract. The antenna is a dual linearly polarized single-offset reflector, illuminated by two side feed arrays operating in X and Ku band respectively. Each array comprises seven compact multimodal horns in quasi rectangular waveguide. The horns are sequentially excited, a couple at a time, for optimum antenna pattern synthesis and secondary beams overlap. Each horn is a multiple step rectangular waveguide structure that provides the proper modal content at aperture, very close to the benchmark patterns analytically synthesized by modal superimposition at feed apertures level. The RF design has been validated through a complete characterization by test of the feeding system, proceeding from the single feeding elements to a complete feeding system composed by 4+4 elements. The measured results showed very good agreement with predictions at each stage of the campaign. Measured pattern has been used as primary source in the antenna model and very good performance have been predicted on secondary beams.

A novel triple-band, self-diplexing feed system operating in K/Ka/EHF bands is presented. The feed system is particularly suitable in space telecom reflector antennas for dual-use applications. Two different RF chain architectures have been traded-off, designed and optimized through full wave modelling, in order to support the optimal choice solution. An EQM of the selected configuration has been realized and subjected to a full qualification test campaign. Very good correlation of the RF performance to the theoretical design has been achieved.

In view of next solar system exploration missions, such as Bepicolombo, Exomars and Juice, this paper overviews the present TAS-I antenna developments focusing on High Gain Antennas (HGA's) for earth-to-planet communications and onboard altimeter/sounder antenna technologies in their specific harsh environment.

The paper presents the array-fed reflector antenna of the CoReH2O (Cold Regions Hydrology High-resolution Observatory) SAR instrument currently being investigated within Phase-A under ESA contract. The antenna is a dual linearly polarized single-offset reflector, illuminated by two side linear arrays operating in X and Ku band respectively. Each array comprises seven compact multimodal horns in quasi rectangular waveguide. These are sequentially excited, a couple at a time, for optimum antenna pattern synthesis and secondary beams overlap. Each horn is a multiple step rectangular waveguide structure that provides the right modal content at aperture, very close to the analytical patterns synthesized through benchmarks. The Ku band feed has been subjected to a pre-development activity aimed at validating the design. The measured results at feed level show good agreement with predictions. Measured pattern has been used as primary source in the antenna model and satisfactory performance have been predicted on radiated beams. The X band feed has been designed with the same electromagnetic model adopted for Ku band and all performances are predicted with the same accuracy. Further breadboarding activities are foreseen in X band, finalized to characterize a reduced dual band feed cluster and the relevant switching systems, taking into account the effect of mutual coupling between the two frequency bands.

A novel self-diplexing feed-system architecture, particularly suitable for high-power multicarrier operated space telecom antennas and conceived for dual/tri-band operation, is addressed in this paper. The proposed architecture is particularly effective in multiple frequency applications where a relatively large bandwidth is requested at the lowest frequency band. Common desirable features of space telecom feed-chains are: negligible passive intermodulation products (PIM-free design), multipaction-free operation, wide operative bandwidth, high isolation (in polarization and frequency), low losses, flexibility in polarization (i.e. dual linear or dual circular). The proposed system architecture is based on a reverse configuration, where the dual polarized high-frequency signals are extracted first from (routed to) the common waveguide of the feed-chain. The building block of this system configuration is a dual-polarization reverse-coupler integrated with a dual-polarization stop-band filter. The latter exploits a two resonant-element cell that exhibits high rejection levels in the stop-band and low reflection levels in the pass-band. A broad-band design of both the coupler and stop-filter is achieved by adopting a quasi-circular ridge common waveguide. The proposed solution is modular in design, providing enough flexibility and allowing customization to different antenna optics and frequency sub-bands. This feature is achieved by replacing specific components in tandem connected through customized PIM-free flanges, where high power signals are present. Hence, PIM avoidance, easy hardware manufacturing and higher tolerance accuracy are possible. Within this framework, different implementations will be highlighted with reference to the most common telecom applications in Ku/Ku+; Ku/K, K/Ka and K/Ka/EHF frequency bands, according to the following frequency plans: 1. Ku/Ku+: Ku-Tx [10.7, 12.75] GHz, Ku-Rx [13.7, 14.5], Ku+:Rx [17.3, 18.4] GHz 2. Ku/K: Ku Tx [10.7, 12.75- GHz, Ku-Rx [13.0, 14.5], K-Tx [17.7, 21.2] GHz 3. K/Ka: K Tx [17.7, 21.2] GHz, Ka-Rx [27.5, 31.0].GHz 4. K/Ka/EHF: K-Tx [19.5, 21.2] GHz, Ka-Rx [29.2, 31.0] GHz, EHF-Rx [43.5, 44] GHz.

This paper describes the design of a dual-frequency compact corrugated horn for use on Ku/K telecommunication satellite antennas. Very stringent requirements for matching, cross polarization and power handling have been satisfied by means of a suitable design strategy. The good comparison between measurements and computations provides a validation of the present design methodology.

The design of a compact dual-band circular corrugated horn for satellite services in the Ku/K-bands is presented in this letter. The horn geometry has been obtained by a suitable design approach, which leads to the definition of a good starting point that is subsequently refined by a rapidly converging optimization technique. The tight agreement between measured and simulated data validates the present design.

This paper presents a reduced order method, based on the Krylov subspace concept and singular value decomposition, for the analysis of conical corrugated horn. The technique has been successfully employed for the design of wideband corrugated horn operating in the Ka band.

Three different RF chain architectures operating in the FSS (Fixed Satellite Services) + BSS (Broadcast Satellite) spectrum are presented and discussed. The RF chains are based on a common wideband corrugated feed horn, but differ on the approach used for bands and polarizations separation. A breadboard of a novel self-diplexed configuration has been designed, manufactured and tested. It proves to be the preferred candidate for bandwidth, losses and power handling. Very good correlation of the RF performance to the theoretical design is found.

A general approach, based on the two-dimensional boundary-element method (BEM), has been proposed to extract the electromagnetic-field singularities in the presence of composed wedges, i.e., those formed by adjacent dielectric and conducting bodies. The method requires the knowledge of the field singularity order and is based on solution factorization into both a regular part and a singular one. Only the regular part has to be determined after extraction. No restrictions are imposed on position and order of singularities since each edge is treated independently of the others. Moreover, the method does not require the solution of further equations or use of special basis functions. It naturally extends the conventional BEM approach, improving its accuracy and convergence performances. Examples are given for a microstrip transmission line with a strip of finite thickness. The results show practicability and advantages of the new approach.