Complex Impedance Transformers Based on Branch-Line Hybrid Couplers

A topology, equations and design methodology for complex impedance-transforming branch-line hybrid couplers are presented. This method also allows the realization of real impedancetransforming to higher impedances. Limitations for real, imaginary and complex impedances are discussed. Test results are shown for a 3 dB 50 to 450 Ω hybrid coupler, at a 2 GHz center frequency, with a 21% bandwidth, an amplitude balance of 4.35 ± 1 dB and a phase balance of 92.16◦ ± 8.8◦. To showcase the complex impedance scenario, two 3 dB 50 Ω to 70 − 200j Ω are measured at a 2 GHz center frequency. One of these couplers uses a technique for reducing the chip size, yielding a 22.5% bandwidth, 4 ± 0.9 dB amplitude balance and 93.22◦ ± 6.74◦ phase balance, while accomplishing a 25% size reductio

Substrate Integrated Waveguides Structures using Frequency Selective Surfaces operating in Stop-Band (SBFSS-SIW)

A novel Substrate Integrated Waveguide (SIW) is proposed using Frequency Selective Surfaces (FSS) operating in Stop- Band (SBFSS-SIW) as metal conductor plates. These structures preserve the propagation properties and the dimensions of the conventional SIW, and have periodic isolated pads that could allow the direct integration of biased active and passive devices on the SIW surface. A set of SBFSS-SIW for X-band have been designed, simulated and experimentally measured to demonstrate that SBFSS-SIWs can behave similar to conventional SIW structures when FSS cells are optimized to work far from its resonance frequencyThis work was supported by the Gobierno del Principado de Asturias under the Plan de Ciencia Tecnología e Innovación (PCTI) by grants BP13042 and BP12032, by the Gobierno del Principado de Asturias and FEDER (Unión Europea) under project GRUPIN14-114, and the Ministerio de Economía y Competitividad under project TEC2014-54005-

Comparison of the near-field measurements between a commercial open-ended rectangular waveguide probe and its equivalent probe in siw technology

2015 AMTA 37th Annual Meeting & Symposiu

Estudio de la Impedancia en la Apertura de Guías Abiertas Sintetizadas en Substrato Microstrip (SIW)

Este trabajo ha sido financiado por el Gobierno del Principado de Asturias mediante el Plan de Ciencia Tecnología e Innovaci´on (PCTI) con las ayudas BP13042 y BP12032, por el Gobierno del Principado de Asturias y FEDER (Unión Europea) a través del proyecto GRUPIN14-114 y por el Ministerio de Economía y competitividad a través del proyecto TEC2014-54005-P.XXX Simposium Nacional de la Unión Científica Internacional de Radio, URSI 201

Risk factors for non-diabetic renal disease in diabetic patients

Background. Diabetic patients with kidney disease have a high prevalence of non-diabetic renal disease (NDRD). Renal and patient survival regarding the diagnosis of diabetic nephropathy (DN) or NDRD have not been widely studied. The aim of our study is to evaluate the prevalence of NDRD in patients with diabetes and to determine the capacity of clinical and analytical data in the prediction of NDRD. In addition, we will study renal and patient prognosis according to the renal biopsy findings in patients with diabetes. Methods. Retrospective multicentre observational study of renal biopsies performed in patients with diabetes from 2002 to 2014. Results. In total, 832 patients were included: 621 men (74.6%), mean age of 61.7 6 12.8 years, creatinine was 2.8 6 2.2 mg/dL and proteinuria 2.7 (interquartile range: 1.2–5.4) g/24 h. About 39.5% (n ¼ 329) of patients had DN, 49.6% (n ¼ 413) NDRD and 10.8% (n ¼ 90) mixed forms. The most frequent NDRD was nephroangiosclerosis (NAS) (n ¼ 87, 9.3%). In the multivariate logistic regression analysis, older age [odds ratio (OR) ¼ 1.03, 95% CI: 1.02–1.05, P < 0.001], microhaematuria (OR ¼ 1.51, 95% CI: 1.03–2.21, P ¼ 0.033) and absence of diabetic retinopathy (DR) (OR ¼ 0.28, 95% CI: 0.19–0.42, P < 0.001) were independently associated with NDRD. Kaplan–Meier analysis showed that patients with DN or mixed forms presented worse renal prognosis than NDRD (P < 0.001) and higher mortality (P ¼ 0.029). In multivariate Cox analyses, older age (P < 0.001), higher serum creatinine (P < 0.001), higher proteinuria (P < 0.001), DR (P ¼ 0.007) and DN (P < 0.001) were independent risk factors for renal replacement therapy. In addition, older age (P < 0.001), peripheral vascular disease (P ¼ 0.002), higher creatinine (P ¼ 0.01) and DN (P ¼ 0.015) were independent risk factors for mortality. Conclusions. The most frequent cause of NDRD is NAS. Elderly patients with microhaematuria and the absence of DR are the ones at risk for NDRD. Patients with DN presented worse renal prognosis and higher mortality than those with NDRD. These results suggest that in some patients with diabetes, kidney biopsy may be useful for an accurate renal diagnosis and subsequently treatment and prognosis