Using a field effect device we modified the number of holes in the surface layers of 4 to 10 unit cell Nd1.2Ba1.8Cu3Oy (NBCO) epitaxial films grown on (100) SrTiO3 substrates. The results obtained on a set of 12 devices demonstrate that it is possible to induce reversible changes of the hole density of NBCO films by field effect. It is found that the field effect becomes less pronounced increasing the film thickness. Insulating–superconducting transition was observed in one 8 unit cell NBCO field effect device.

No abstract

No abstract

No abstract

(equal to 0.39 ϫ 0.39 g, where g is the guided wavelength at the center frequency). The filter responses are characterized by using an HP 8510C network analyzer and compared with the EM simulation, as also shown in Figure 4. The measured passband has a center frequency f 0 of 2.4 GHz, a minimum S 11 of 15 dB, a maximum S 21 of 1.7 dB, and a 3-dB fractional bandwidth (FBW) of 4.9%. A pair of transmission zeros can be obviously observed near the two-side skirt of passband at 2.2 and 2.7 GHz, thus the selectivity of the proposed design is much better than that of the BPF using the H-shaped fractal [4]. The slight difference between the simulation and measurement might be due to fabrication errors or the variation of material properties. It is verified that the proposed BPF with the SFR has a good potential for the mobile wireless communication system. CONCLUSIONA new microstrip dual mode BPF using the Sierpinski fractalbased resonator (SFR) has been designed and fabricated. When increasing the iteration order of the SFR from 0th to 3rd, the resonant peak of the SFR is shifted to lower frequency. Therefore, a 3rd order SFR is used to design a high performance dual mode BPF due to its miniaturized property. A miniature and low insertion dual-mode BPF centered at 2.4 GHz using the proposed 3rd SFR is designed, fabricated, and characterized to verify the design concept. The measured results have a minimum S 11 of 15 dB, a maximum S 21 of 1.7 dB, a 3-dB FBW of 4.9%, and a pair of transmission zeros observed near the two-side skirt of passband at 2.2 and 2.7 GHz, thus improving the selectivity of the proposed design. Additionally, the measurement results are in agreement with the simulation results. , a twin-L-probes coupled patch antenna was designed [7]. It can enhance the bandwidth and gain of a patch antenna to 25% (SWR Ͻ 1.5) and 10 dBi. Even though it has one patch only, its feeding structure is relatively complicated. A T-junction power divider is required to connect the two feeding probes and the numbers of the feeding probes are doubled. This increases the manufacturing cost of the antenna, especially in antenna array design. In this article, it is demonstrated that one meandering probe can replace the complicated twin-L-probes design to feed the long rectangular. Other than wideband and high gain, the proposed antenna also performs characteristics of low cross-polarized level and symmetric radiation pattern in the two principle planes. ANTENNA GEOMETRYThe geometry of the proposed antenna is shown in Figure 1. The antenna consists of an electrically long rectangular patch, a meandering probe, and a square ground plane with 300 mm in length. The centers of the patch and the ground plane are aligned together. The patch, which has width W ϭ 180 mm (1.06 0 ) and length L ϭ 60 mm (0.35 0 ), is located at a height of H p ϭ 17.5 mm (0.1 0 ) above the ground plane and supported by foam spacer (air substrate). The meandering probe is made by bending a copper strip, which has a rectangular cross-section with thickness 0.5...