This work presents the design and prototyping of a reconfigurable phased array in Ku band (16 to 18 GHz) implemented in waveguide technology. The design is based on the use of a novel seamless waveguide module integrating four reconfigurable phase shifters to adjust the relative phase shift between the unitary elements of a linear array, which are illuminated uniformly by a corporate waveguide feeding network. The phase shifters are implemented by a 90 ○ hybrid coupler in waveguide technology where two of its ports are loaded with a tunable reactive load, implemented in this proof of concept with a tuning screw. The four phase shifters have been manufactured in a single part using direct metal laser sintering, avoiding the losses related to bad electric contacts and misalignments associated to multipart devices. This also simplifies the assembly of the full phased array, leading to a modular approach with three parts whose design can be addressed separately. The experimental results for the complete array antenna show great performance and demonstrate that the main-lobe of the radiation pattern can be effectively scanned continuously between the angles −25 ○ and 25 ○ , with a high efficiency in the whole design band thanks to the proposed waveguide implementation.

and experiment. The measured stopband of the filter was found to be 60 dB up to 44f 0 and 110 dB up to 24f 0 . | S U M M A R YThis letter has described an investigation of a multilayered, multi-conductor stripline resonator, which consists of metaldielectric structure suspended in the middle of a metallic case. All the conductors in the resonator have strong mutual inductive coupling, and hence the previously proposed theory for interdigital microstrip resonator can be incorporated. Increase in the number of the conductors leads to raising the unloaded Q-factor and lowering the resonant frequency; moreover, with tinier interlayers, the effects magnify.A 4-pole passband filter was designed and fabricated, based on the resonator. It was found that, for the central frequency of 360 MHz and 10% fractional bandwidth, the overall size of the filter was only 15.5 3 31.75 3 8.45 mm 3 (0.019k 3 0.038k 3 0.013k). The fabricated filter has upper stopband up to 44f 0 at level 260 dB and 24f 0 at level 2110 dB. AbstractIn this article, a linearly polarized 4-element linear array in Ku band is presented. The single element consists of a circular microstrip patch capacitively coupled to a printed 2216 | MURIEL-BARRADO ET AL.

A circularly polarized double-stacked patch subarray antenna fed by a hexagonal radial line with internal circular coupling patches is proposed. The antenna works at K band (19.7 GHz -20.2 GHz) with LHCP. On the one hand, the design approach consists of a coupling study based on the simulation of a periodic parallel-plate waveguide as a first approximation of the radial line. On the other hand, a phase compensation method by rotation is applied in order to adjust the radiating phase of each element of the subarray, which are separated O.Tko. Thus, the subarray is uniformly fed in terms of amplitude and phase. An axial ratio below 1 dB is achieved for the entire frequency band, with a gain of 24 dB and a total efficiency of 87% The radial line has been modelled as a hexagon to perform this analysis in larger arrays in future design steps.

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