Compact double-p slotted inset-fed microstrip patch antenna on high dielectric substrate.

This paper presents a compact sized inset-fed rectangular microstrip patch antenna embedded with double-P slots. The proposed antenna has been designed and fabricated on ceramic-PTFE composite material substrate of high dielectric constant value. The measurement results from the fabricated prototype of the antenna show -10 dB reflection coefficient bandwidths of 200 MHz and 300 MHz with center resonant frequency of 1.5 GHz and 4 GHz, respectively. The fabricated antenna has attained gains of 3.52 dBi with 81% radiation efficiency and 5.72 dBi with 87% radiation efficiency for lower band and upper band, respectively. The measured E- and H-plane radiation patterns are also presented for better understanding. Good agreement between the simulation and measurement results and consistent radiation patterns make the proposed antenna suitable for GPS and C-band applications.

Low-cost dielectric substrate for designing low profile multiband monopole microstrip antenna.

This paper proposes a small sized, low-cost multiband monopole antenna which can cover the WiMAX bands and C-band. The proposed antenna of 20 × 20 mm(2) radiating patch is printed on cost effective 1.6 mm thick fiberglass polymer resin dielectric material substrate and fed by 4 mm long microstrip line. The finite element method based, full wave electromagnetic simulator HFSS is efficiently utilized for designing and analyzing the proposed antenna and the antenna parameters are measured in a standard far-field anechoic chamber. The experimental results show that the prototype of the antenna has achieved operating bandwidths (voltage stand wave ratio (VSWR) less than 2) 360 MHz (2.53-2.89 GHz) and 440 MHz (3.47-3.91 GHz) for WiMAX and 1550 MHz (6.28-7.83 GHz) for C-band. The simulated and measured results for VSWR, radiation patterns, and gain are well matched. Nearly omnidirectional radiation patterns are achieved and the peak gains are of 3.62 dBi, 3.67 dBi, and 5.7 dBi at 2.66 GHz, 3.65 GHz, and 6.58 GHz, respectively.

Bandwidth enhancement of a dual band planar monopole antenna using meandered microstrip feeding.

A meandered-microstrip fed circular shaped monopole antenna loaded with vertical slots on a high dielectric material substrate (ε r = 15) is proposed in this paper. The performance criteria of the proposed antenna have been experimentally verified by fabricating a printed prototype. The experimental results show that the proposed antenna has achieved wider bandwidth with satisfactory gain by introducing meandered-microstrip feeding in assistant of partial ground plane. It is observed that, the -10 dB impedance bandwidth of the proposed antenna at lower band is 44.4% (600 MHz-1 GHz) and at upper band is 28% (2.25 GHz-2.95 GHz). The measured maximum gains of -1.18 dBi and 4.87 dBi with maximum radiation efficiencies have been observed at lower band and upper band, respectively. The antenna configuration and parametric study have been carried out with the help of commercially available computer-aided EM simulator, and a good accordance is perceived in between the simulated and measured results. The analysis of performance criteria and almost consistent radiation pattern make the proposed antenna a suitable candidate for UHF RFID, WiMAX, and WLAN applications.

Coronary angiographic profile in bangladeshi patients with metabolic syndrome and ischemic heart disease.

The metabolic syndrome, which is characterized by a constellation of fasting hyperglycemia, hypertriglyceridemia, low HDL cholesterol, hypertension, and/or abdominal obesity, is a risk factor for the development of coronary artery disease (CAD) and cardiovascular events. We evaluated interrelationships between angiographic CAD and the metabolic syndrome, in 478 patients who were referred for coronary angiography to evaluate suspected myocardial ischemia in the department of cardiology of BSMMU between June 2007 and May 2008. We applied the criteria for the metabolic syndrome proposed by ATP III guideline. Study populations were divided into two groups on the basis of presence or absence of metabolic syndrome. Age was similar in both groups. Body mass index (BMI) was higher (26.22 ± 1.94 vs. 22.07 ± 1.55) in metabolic syndrome group (p ≤ 0.0001). All parameters, waist circumference (103.16 ± 10.21 vs. 91.45 ± 7.61) cm, blood pressure both systolic (141.34 ± 21.49 vs. 127.94 ± 13.01) and diastolic (86.8 5 ± 8.42 vs. 79.28 ± 7.77) mm of Hg, serum triglyceride (248.32 ± 77.88 vs. 128.35 ± 19.00)mg/dl, fasting blood glucose (125.40 ± 22.86 vs. 95.65 ± 10.63)mg/dl were significantly higher in metabolic syndrome group (p value=0.0001), whereas HDL (33.10 ± 6.55 vs. 39.30 ± 6.17)mg/dl was lower (p value = 0.0001). More subjects in metabolic syndrome were having type B (55.60% vs. 31.00%) and type C (9.50% vs. 2.70%) lesion as compared to non-metabolic syndrome group. Involvement of left main artery was more (4.80% vs. 0.90%) in metabolic syndrome group. Metabolic syndrome has primary predictive ability for CAD. A metabolic profile should form part of the risk assessment in all patients with coronary disease, not just those who are obese.