fed monopole antenna having frequency band-notch function, IEEE Microwave Wireless Compon Lett 15 (2005), 766-768. 2. FCC first report and order on ultra-wideband technology,2002. Planar ultrawideband antennas with multiple notched bands based on etched slots on the patch and/or split ring resonators on the feed line, principle applied to the design of metasurfaces and metamaterials, Phys Rev Lett 93 (2004), A miniature UWB planar monopole antenna with 5-GHz band-rejection filter and the time-domain characteristics,ABSTRACT: This article presents an ultra-wideband (UWB). RF receiver that includes a low noise amplifier (LNA) and a singlebalanced mixer (SBM). The LNA uses an RC shunt feedback technique for broadening the bandwidth. Besides, an inductor is used as an Figure 8 Measured y-z plane and x-z plane radiation pattern for proposed antenna at (a) 3.5 GHz and (b) 9 GHz 232interstage match at the cascode LNA that efficiently improves the flatness of the cascode LNA. The RC shunt feedback is also applied to the g m stage of mixer for the input impedance match. The low-pass IF load is used to improve the LO/IF isolation of the SBM. The measured results of the UWB RF receiver are a conversion gain of 17.5-19.5 dB, a double side-band noise figure of 5.25-6.89 dB at 100 MHz IF frequency under an LO power of 2 dBm, a minimal 1-dB compression point (P 1dB ) of À31 dBm, an input third order intercept point of À12 dBm, the isolations among all ports of better than À40 dB. The total power consumption is 29.1 mW.ABSTRACT: A dual-band microstrip bandpass filter is proposed. With the assistance of modified short-circuit quarter-wavelength resonators, the dual-band bandpass filter can be developed. Theoretical analysis and design procedures are provided; the prototypical bandpass filter with dual passbands is fabricated and measured as well. Well-matched simulated results and experimental data validate the proposed filter.

erally speaking, the measured transfer characteristics of the fabricated filter with the proposed DGS show steep band-rejection property as expected. CONCLUSIONWe have presented a novel meander-slot DGS with high quality factor and compact layout. And how the structural dimensions affect characteristics of this DGS has been analyzed. On the basis of the analysis, an experiential method for designing this DGS is proposed. Finally, cascaded meander-slot DGSs are applied to a microstrip narrow-band stop filter. The measured results of the filter illuminate the applicability of the proposed DGS in practical engineering. Compared with conventional DGSs, the meander-slot DGS is quite competitive, accompanied with good resonance and compactification. It is predicted to be widely used in design of passive and active components, such as antennas, mixers, amplifier, multipliers and so on. Particularly meander-slot DGS will be quite applicable in the circumstances that keenedged filtration and integrated miniaturization are comparably required. Certainly it will show imaginable potential in current flourishing RFIC and MMIC industry. defected ground structures (DGSs) including left-handed features,