This article presents a six-pole high-temperature superconducting (HTS) filter with a fractional bandwidth (FBW) of 0.09% at 3.3 GHz. Twin-spiral resonators with a high quality factor (Q u ) of 69,000 are used in the design procedure. The measured results of the filter exhibit a low insertion loss of 0.62 dB and are in good Figure 6 Layout of the proposed bandstop filter using DMS Figure 7 The photograph of the fabricated bandstop filter. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com] Figure 8 Comparison between the simulated (solid line) and measured (dash line) results of the bandstop filter. [Color figure can be viewed in the online issue, which is available at wileyonlinelibrary.com]

Band-pass filters using complementary split ring resonator (CSRR) are proposed in this article. Two-cascaded and threecascaded band-pass filters using CSRR are designed, simulated, fabricated and measured.

A blockage of the middle cerebral artery (MCA) on the cortical branch will seriously affect the blood supply of the cerebral cortex. Real-time monitoring of MCA hemodynamic parameters is critical for therapy and rehabilitation. Optical coherence tomography (OCT) is a powerful imaging modality that can produce not only structural images but also functional information on the tissue. We use OCT to detect hemodynamic changes after MCA branch occlusion. We injected a selected dose of endothelin-1 (ET-1) at a depth of 1 mm near the MCA and let the blood vessels follow a process first of occlusion and then of slow reperfusion as realistically as possible to simulate local cerebral ischemia. During this period, we used optical microangiography and Doppler OCT to obtain multiple hemodynamic MCA parameters. The change trend of these parameters from before to after ET-1 injection clearly reflects the dynamic regularity of the MCA. These results show the mechanism of the cerebral ischemia-reperfusion process after a transient middle cerebral artery occlusion and confirm that OCT can be used to monitor hemodynamic parameters.

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Compact π‐shape defected ground structure (DGS) and π‐shape defected microstrip structure (DMS) are proposed. Their resonant characteristics are analyzed using HFSS 12. Two band‐stop filters based on π‐shape DGS and π‐shape DMS are presented. One filter is composed of π‐shape DMS. Another filter is composed of π‐shape DMS and π‐shape DGS. The resonant characteristics of the filters can be changed by changing the structure parameters, especially the length a. Using π‐shape DGS, the performance of the band‐stop filter is improved and the area of the filter remains the same. Both two proposed band‐stop filters have two transmission zeros at each edge of the stop‐band. Finally, two band‐stop filters are fabricated and measured. The simulated results are basically consistent with the measured ones. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2504–2507, 2014