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A compact asymmetric coplanar strip fed monopole antenna for multiband applications is presented. The antenna exhibits three resonances around 1.8, 2.4, and 5.6 GHz covering the DCS/PCS/UMTS/IEEE 802.11b/g/IEEE802.11a/HIPERLAN2 bands. The multiband characteristic of the antenna is due to the various meandered current paths excited in the radiating structure. The antenna has an overall dimension of only 28 x 30 [mm.sup.2] when printed on a substrate of dielectric constant 4.4. The uniplanar design, simple feeding technique and compactness make it easy for the integration of the antenna into circuit boards. Details of the antenna design, experimental and simulated results are presented and discussed. Index Terms--Asymmetric coplanar strip (ACS), mobile antennas, monopole antennas, multiband antennas, printed antennas, uniplanar.

A novel compact microstrip fed dual-band coplanar antenna for wireless local area network is presented. The antenna comprises of a rectangular center strip and two lateral strips printed on a dielectric substrate and excited using a 50 [ohm] microstrip transmission line. The antenna generates two separate resonant modes to cover 2.4/5.2/5.8 GHz WLAN bands. Lower resonant mode of the antenna has an impedance bandwidth (2:1 VSWR) of 330 MHz (2190-2520 MHz), which easily covers0 the required bandwidth of the 2.4 GHz WLAN, and the upper resonant mode has a bandwidth of 1.23 GHz (4849-6070 MHz), covering 5.2/5.8 GHz WLAN bands. The proposed antenna occupy an area of 217 [mm.sup.2] when printed on FR4 substrate ([[epsilon].sub.r] = 4.7). A rigorous experimental study has been conducted to confirm the characteristics of the antenna. Design equations for the proposed antenna are also developed. Index Terms--Coplanar wavegnide, dual-band antennas, printed antennas, wireless local area networks (WLANs).

TeO2 particle-filled PTFE composites were prepared by the powder processing technique. The structure and microstructure of the composites were investigated by X-ray diffraction and scanning electron microscopic methods. The effect of the ceramic content (0–0.6 volume fraction) of TeO2 on the dielectric properties of the composites was studied at 1 MHz and 7 GHz. The dielectric constant and dielectric loss increased with an increase in the TeO2 content. For 60 vol% of TeO2, the composite has a dielectric constant of 5.4 and a loss tangent of 0.006 at 7 GHz. The measured dielectric constant (ℇr) is compared with the effective dielectric constant calculated using different theoretical models. The observed dielectric constants are in agreement with that calculated using effective medium theory. The coefficient of thermal expansion of the composites decreases with the TeO2 content, reaching a minimum of 32 ppm/°C for 60 vol% loading. [ABSTRACT FROM AUTHOR]

A compact asymmetric coplanar strip, fed monopole antenna for multiband applications is presented. The antenna exhibits three resonances around 1.8, 2.4, and 5.6 GHz covering the DCS/PCS/UMTS/IEEE 802.11b/g/IEEE802.11a/HIPERLAN2 bands. The multiband characteristic of the antenna is due to the various meandered current paths excited in the radiating structure. The antenna has an overall dimension of only 28 × 30 mm2 when printed on a substrate of dielectric constant 4.4. The uniplanar design, simple feeding technique and compactness make it easy for the integration of the antenna into circuit boards. Details of the antenna design, experimental and simulated results are presented and discussed. [ABSTRACT FROM AUTHOR]

Development of a compact microstrip-fed, branched monopole antenna for ultra wide band (UWB) applications is presented. By suitably embedding branches on the top edge of the strip monopole, an UWB response can be easily achieved by merging different resonances. The simulated and experimental results demonstrate that the proposed antenna achieves more than 3:1 impedance bandwidth for 2:1 VSWR criteria. The antenna exhibits nearly omni directional radiation characteristics and moderate gain in the entire band. The proposed antenna is printed on a FR4 substrate of ℇr = 4.4 and thickness h = 1.6 mm and having an overall dimension of 65 × 35 mm2 including the ground plane. The parameters that affect the performance of the antenna are presented and discussed. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 45–47, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22045 [ABSTRACT FROM AUTHOR]

Background: Co-existence of type 2 diabetes and hypothyroidism is an emerging trend observed in clinical practice. Although the effects of isolated type 2 diabetes and hypothyroidism are well known, there are limited studies addressing the metabolic complications when these two conditions co-exist. The aim of the present study was to assess the interaction between type 2 diabetes and hypothyroidism with respect to glucose tolerance, dyslipidemia and redox balance in a state were these two diseases coexist. Methods: Sixty male Wistar Albino rats were randomised into six groups. Group 1: control, Group 2: overt hypothyroidism, Group 3: mild hypothyroidism, Group 4: type 2 diabetes, Group 5: mild hypothyroidism + type 2 diabetes, Group 6: overt hypothyroidism + type 2 diabetes. Experimental hypothyroidism was created by the administration of propyl-2-thiouracil and type 2 diabetes by feeding rats with 60% fructose (w/w). The duration of the study was 6 weeks. All the parameters were estimated at the start (basal) and the end of the study. Intraperitoneal glucose tolerance test was carried out and area under curve (AUC) calculated to assess the glucose tolerance. Thyroid profile, lipid profile and oxidative stress parameters were also measured. Results: Plasma TSH level was elevated 3-fold in the mild hypothyroid group and 15.2-fold in the overt hypothyroid group in comparison to the control group. Thyroid profile was found to be normal in type 2 diabetic group. There was no significant difference between hypothyroidism and hypothyroidism + diabetes groups with respect to thyroid profile. Among the six groups the degree of glucose intolerance was found to be maximum for overt hypothyroidism + diabetes group, followed by diabetes group and overt hypothyroidism group. An interesting finding was that glucose intolerance was significantly reduced in mild hypothyroidism + diabetes group (increase in AUC: 48.04%) in comparison with isolated diabetes group (increase in AUC: 71.63%). Similar results were obtained with parameters of oxidative stress. Oxidative stress was observed in overt hypothyroidism + diabetes, diabetes, overt hypothyroidism groups with severity decreasing in that order. Coexistence of mild hypothyroidism with diabetes decreased oxidative stress in comparison with isolated diabetes group. There was no statistical difference in lipid profile between mild hypothyroidism + diabetes and isolated diabetes group. Conclusion: Presence of mild hypothyroidism in type 2 diabetes confers a protective effect with respect to glucose tolerance and redox balance whereas presence of overt hypothyroidism in type 2 diabetes has a deleterious effect. The increased incidence of hypothyroidism in diabetes, especially subclinical hypothyroidism, could be a reflection of a physiological attempt by the body to mitigate damage wrought by diabetes. [ABSTRACT FROM AUTHOR]