A dual‐band stub (DBS) in a hybrid lumped and distributed configuration is presented in this paper, which comprises one lumped kernel circuit unit cell (KCUC) centered between two uniform transmission lines. Image parameter theory is imposed to extract the DBS phase and impedance bandwidth properties. An odd‐even mode resonant frequency ratio is defined, capable of determining all the DBS element values as well as regulating the DBS size and its second working bandwidth. By converting the lumped KCUC into a quasi‐lumped microstrip topology, a purely planar DBS is automatically implemented by employing the aggressive space mapping (ASM). Through the customized ASM process, the finalized DBS dimensions can be generated within just a few full‐wave simulations. The relatively high accuracy and efficiency of the ASM are affirmed by comparing its performance to those of the traditional direct optimization algorithms. As an example, a DBS with WLAN dual frequencies and extended bandwidth is designed and fabricated. The measured results agree well with the simulated results, justifying the DBS properties and its ad hoc ASM optimization technique.
A dual-polarized wideband Fabry-Perot (FP) antenna based on a wedgeshaped phase correcting structure (WPCS) is proposed. The antenna adopts a wideband dual-linear polarized slot-coupled antenna as a primary antenna, and adopts a single-layer FSS structure with positive reflection phase gradient characteristics as a partially reflecting surface (PRS) of the FP resonator, to optimally excite the FP cavity resonances within a wide operating band. Moreover, a small circular metal patch array is printed on the other side of the FSS unit structure. The small circular patch array effectively increases the reflection amplitude without changing the positive reflection phase gradient characteristics of the PRS, which improves the FP antenna gain. In addition, a highly graded WPCS is loaded in the resonant cavity to properly compensate the phase between different reflection paths inside the resonant cavity, which enhances the gain of the FP antenna in a wide band. Finally, the measured peak gains of the FP antenna under the excitation of Port 1 and Port 2 are 16.0 dBi and 15.89 dBi, respectively, and the gain enhancement can reach up to 3 dBi after loading the WPCS. The measured 10-dB impedance-matching operating bandwidth of dual-polarized common coverage is 14.08 to 16.45 GHz (15.53%).
Cardiovascular complications represent a leading cause of mortality in patients with type 2 diabetes mellitus (T2DM). During such complicated progression, subtle variations in the cardiovascular risk (CVR)-related biomarkers have been used to identify cardiovascular disease at the incipient stage. In this study we attempt to integrally characterize the progression of cardiovascular complications and to assess the beneficial effects of metformin combined with salvianolic acid A (Sal A), in Goto-Kakizaki (GK) rats with spontaneous T2DM. The rats were treated with metformin ( , ip) at ages from 8 to 22 weeks. During the treatment, the levels of asymmetric dimethylarginine, L-arginine, superoxide dismutase, malondialdehyde, glucose, high density lipoprotein and low density lipoprotein were assessed. Based on alterations in these biomarkers, a mini-network balance model was established using matrixes and vectors. Radar charts were created to visually depict the disruption of CVR-related modules (endothelial function, oxidative stress, glycation and lipid profiles). The description for the progression of cardiovascular disorder was quantitatively represented by u, the dynamic parameter of the model. The modeling results suggested that untreated GK rats tended to have more severe cardiovascular complications than the treatment groups. Metformin monotherapy retarded disease deterioration, whereas the combination treatment ameliorated the disease progression via restoring the balance. The current study, which focused on the balance of the mini-network and interactions among CVR-related modules, proposes a novel method for evaluating the progression of cardiovascular complications in T2DM as well as a more beneficial intervention strategy.
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