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from 10-14% in the same range. We present better efficiency, which is in part benefited from the GaAs substrate. Our significantly high FOM and PAE demonstrate that it is well suited for the low-cost UWB power amplifiers. CONCLUSIONSIn this letter, we present an integrated distributed power distributed amplifier with a low-cost 2-lm GaAs HBT technology. We use the tapered collector line structure combined with the input capacitive coupling technique to improve the bandwidth and power efficiency. The measurement results give the gain of 8.1 dB with a gain flatness of 60.5 dB over a frequency range from 1 to 12 GHz. The 3-dB bandwidth is up to 12.24 GHz. The output 1-dB compressing point is 13.9 dBm at 5 GHz, and the associated PAE is 21.9%. The chip area is 0.99 mm 2 , and the power dissipation of the amplifier is 98 mW from a 2-V supply. Good agreement between the simulation and measurement results is achieved. Our work presents very good performance considering the trade-off of gain-bandwidth, efficiency, output power, and technologies among the recently published distribution amplifiers.ABSTRACT: A new printed wide slot antenna with single-and dualband notch behavior is presented. The base of antenna is a simple forkshaped radiating patch, which covers the ultra-wideband (UWB) frequency range. By using additional protrudent open circuit stubs on the base patch, multiband notch behavior is obtained. Effects of varying the added stubs parameters on the antenna performance show that the center frequency of band rejections can be finely tuned. The proposed dual-band notch antenna covers 2.4-10 GHz with two bands rejection Figure 8 Measured radiation pattern of the proposed antenna. (a) 4, (b) 6, (c) 7, and (d) 9 GHz

In this letter the reflection and transmission properties of reinforced concrete specimens irradiated by a modified, high-gain, ultra-wideband antipodal Vivaldi antenna (MAVA) are investigated numerically and experimentally. First, the influence of the interfaces between free space and concrete, and a reinforced bar (rebar) cell embedded in concrete on the reflection property is investigated at frequency range from 0.65-3.5 GHz. Second, the transmission property of the reinforced concrete specimens is investigated at 2.45 GHz using a small resonant microstrip patch antenna embedded in concrete at the location of a rebar cell with different values of cell parameter. It is shown that the reflection from the free space-concrete interface of specimens with and without rebars provides the most critical effect on the reflection and transmission properties of the specimens. It is also shown that maximum transmission can be achieved when the patch antenna is located in the centre of the rebar cell. The measured results are in good agreement with the numerical results. The results of this letter can be used for nondestructive testing of reinforced concrete specimens and for wireless power transmission to sensors embedded in reinforced concrete.

frequencies of the bandwidth although the level of reflection is significantly decreased in overall compared with the initial design. The optimum designs for the case of two and four protruding vias are shown in Table 2. The responses corresponding to these designs are shown in Figures 6(b) and 6(c). CONCLUSIONSWe demonstrate a technique to broaden the useable bandwidth of the CBCPW-to-SIW transitions. The transition structures are modified by introducing-as the tuning elements-metalized vias partially protruding into the substrate in the transition region. The vias can be easily implemented within the SIC/SIW manufacturing technology. The transition geometry as well as the location and the size of extra vias are adjusted using the adaptive design specifications algorithm exploiting coarse-discretization EM transition models. This allows us to find the optimal designs at a low-computational cost. 10. N.V. Queipo, R.T. Haftka, W. Shyy, T. Goel, R. Vaidynathan, and P.K. Tucker, Surrogate-based analysis and optimization, Prog Aerosp Sci 41 (2005), 1-28. 11. CST Microwave Studio, ver. 2010, CST AG, CST Microwave Studio Germany, 2010. 12. T.G. Kolda, R.M. Lewis, and V. Torczon, Optimization by direct search: new perspectives on some classical and modern methods, SIAM Rev 45 (2003), 385-482. 13. S. Koziel, Adaptively adjusted design specifications for efficient optimization of microwave structures, Prog Electromagn Res B (PIER B) 21 (2010), 219-234.ABSTRACT: A novel ultra wideband (UWB) antenna with coplanar waveguide (CPW) feed, consisting of a circular patch and a ground ABSTRACT: A novel ultra-wide band bandpass filter with notched band is presented. Multi-mode resonator is realized using a stepped-impedance slotline. The resonator is orthogonally coupled to the microstrip feed lines, and ultra-wide passband is obtained. Microstrip open loop resonators are loaded on the slotline, and notched band from 5.1 to 5.3 GHz is achieved. The filter is designed, fabricated, and measured. Good agreement is achieved between measured and predicted results.

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