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A three-dimensional (3-D) printed Fabry-Pérot resonator antenna (FPRA), which designed with a paraboloid-shape superstrate for wide gain bandwidth is proposed. In comparison with the commonly-adopted planar superstrate, the paraboloid-shape superstrate is able to provide multiple resonant heights and thus satisfy the resonant condition of the FPRA in a wide frequency band. A FPRA working at 6 GHz is designed, fabricated, and tested. Considering the fabrication difficulty caused by its complex structure, the prototype antenna was fabricated by using the 3-D printing technology, i.e., all components of the prototype antenna were printed with photopolymer resin and then treated by the surface metallization process. Measurement results agree well with the simulation results, and show the 3-D printed FPRA has a |S 11 | < −10 dB impedance bandwidth of 12.4%, and a gain of 16.8 dBi at its working frequency of 6 GHz. Moreover, in comparison with the planar superstrate adopted in traditional FPRAs, the paraboloid-shape superstrate of the proposed FPRA significantly improves the 3-dB gain bandwidth from 6% to 22.2%.

A 3D printed metallized Fabry-Perot cavity antenna centred at 5.8 GHz is presented in this letter. A non-uniform grid superstrate and a choke groove are employed in the Fabry-Perot cavity antenna to improve the input bandwidth and decrease the side lobes. By using the non-uniform superstrate, the |S 11 | ← 10 dB bandwidth is enhanced to approximately 6.4% (from 5.65 to 6.02 GHz). The side lobes decrease to −14.03 and −21.62 dB on E and H planes by the choke groove. The designed antenna is fabricated by using a stereolithography-based 3D printing technique for verification, whose weight is only 13% of the one fabricated with copper. The measured result agrees well with the simulated one.

For certain product varieties, Murre's conjecture on Chow groups is investigated. More precisely, let k be an algebraically closed field, X be a smooth projective variety over k and C be a smooth projective irreducible curve over k with function field K: Then we prove that if X (resp. X K ) satisfies Murre's conjectures (A) and (B) for a set of Chow-Künneth projectors f 0 i ;0 Ä i Ä 2dimX g of X (resp. for f. 0 i / K g of X K ) and if for any j , CH j alg .X K IQ/ Â Ker.. 0 2j / K /, then the product variety X C also satisfies Murre's conjectures (A) and (B). As consequences, it is proved that if C is a curve and X is an elliptic modular threefold over k (an algebraically closed field of characteristic 0 ) or an abelian variety of dimension 3, then Murre's conjecture (B) is true for the fourfold X C:

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