At the National Synchrotron Radiation Research Center, a small/wide‐angle X‐ray scattering (SAXS/WAXS) instrument has been installed at the BL23A beamline with a superconducting wiggler insertion device. This beamline is equipped with double Si(111) crystal and double Mo/B4C multilayer monochromators, and an Si‐based plane mirror that can selectively deflect the beam downwards for grazing‐incidence SAXS (GISAXS) studies of air–liquid or liquid–liquid interfaces. The SAXS/WAXS instrument, situated in an experimental hutch, comprises collimation, sample and post‐sample stages. Pinholes and slits have been incorporated into the beam collimation system spanning a distance of ∼5 m. The sample stage can accommodate various sample geometries for air–liquid interfaces, thin films, and solution and solid samples. The post‐sample section consists of a 1 m WAXS section with two linear gas detectors, a vacuum bellows (1–4 m), a two‐beamstop system and the SAXS detector system, all situated on a motorized optical bench for motion in six degrees of freedom. In particular, the vacuum bellows of a large inner diameter (260 mm) provides continuous changes of the sample‐to‐detector distance under vacuum. Synchronized SAXS and WAXS measurements are realized via a data‐acquisition protocol that can integrate the two linear gas detectors for WAXS and the area detector for SAXS (gas type or Mar165 CCD); the protocol also incorporates sample changing and temperature control for programmable data collection. The performance of the instrument is illustrated via several different measurements, including (1) simultaneous SAXS/WAXS and differential scanning calorimetry for polymer crystallization, (2) structural evolution with a large ordering spacing of ∼250 nm in a supramolecular complex, (3) SAXS for polymer blends under in situ drawing, (4) SAXS and anomalous SAXS for unilamellar lipid vesicles and metalloprotein solutions, (5) anomalous GISAXS for oriented membranes of Br‐labeled lipids embedded with peptides, and (6) GISAXS for silicate films formed in situ at the air–water interface.

At the National Synchrotron Radiation Research Center (NSRRC), which operates a 1.5 GeV storage ring, a dedicated small-angle X-ray scattering (SAXS) beamline has been installed with an in-achromat superconducting wiggler insertion device of peak magnetic field 3.1 T. The vertical beam divergence from the X-ray source is reduced significantly by a collimating mirror. Subsequently the beam is selectively monochromated by a double Si(111) crystal monochromator with high energy resolution (DeltaE/E approximately 2 x 10(-4)) in the energy range 5-23 keV, or by a double Mo/B4C multilayer monochromator for 10-30 times higher flux ( approximately 10(11) photons s(-1)) in the 6-15 keV range. These two monochromators are incorporated into one rotating cradle for fast exchange. The monochromated beam is focused by a toroidal mirror with 1:1 focusing for a small beam divergence and a beam size of approximately 0.9 mm x 0.3 mm (horizontal x vertical) at the focus point located 26.5 m from the radiation source. A plane mirror installed after the toroidal mirror is selectively used to deflect the beam downwards for grazing-incidence SAXS (GISAXS) from liquid surfaces. Two online beam-position monitors separated by 8 m provide an efficient feedback control for an overall beam-position stability in the 10 microm range. The beam features measured, including the flux density, energy resolution, size and divergence, are consistent with those calculated using the ray-tracing program SHADOW. With the deflectable beam of relatively high energy resolution and high flux, the new beamline meets the requirements for a wide range of SAXS applications, including anomalous SAXS for multiphase nanoparticles (e.g. semiconductor core-shell quantum dots) and GISAXS from liquid surfaces.

Using a superconducting-wavelength-shifter X-ray source with a photon flux density of 10(11)-10(13) photons s(-1) mrad(-1) (0.1% bandwidth)(-1) (200 mA)(-1) in the energy range 5-35 keV, three hard X-ray beamlines, BL01A, BL01B and BL01C, have been designed and constructed at the 1.5 GeV storage ring of the National Synchrotron Radiation Research Center (NSRRC). These have been designed for structure-related research using X-ray imaging, absorption, scattering and diffraction. The branch beamline BL01A, which has an unmonochromatized beam, is suitable for phase-contrast X-ray imaging with a spatial resolution of 1 microm and an imaging efficiency of one frame per 10 ms. The main beamline BL01B has 1:1 beam focusing and a medium energy resolution of approximately 10(-3). It has been designed for small-angle X-ray scattering and transmission X-ray microscopy, used, respectively, in anomalous scattering and nanophase-contrast imaging with 30 nm spatial resolution. Finally, the branch beamline BL01C, which features collimating and focusing mirrors and a double-crystal monochromator for a high energy resolution of approximately 10(-4), has been designed for X-ray absorption spectroscopy and high-resolution powder X-ray diffraction. These instruments, providing complementary tools for studying multiphase structures, have opened up a new research trend of integrated structural study at the NSRRC, especially in biology and materials. Examples illustrating the performances of the beamlines and the instruments installed are presented.

Abstract-A compact stack antenna consisting of square loop resonators, aperture couples, feed line and the perturbation for dualband and circular polarization (CP) applications is proposed in this paper. This perturbation applies both dual-mode and orthogonal mode effects existing in the square loop resonator to present wide-band and CP characteristics simultaneously. The stack antenna presents the desired bands of 2.46 GHz with bandwidth (BW) = 160 MHz (6.58%) and 5.28 GHz with BW = 450 MHz (8.52%). The circular polarizations for dual-band are demonstrated with axial ratio (AR) spectrum and orthogonal modes. The proposed antenna is successfully simulated and measured with frequency responses, radiation patterns and current distributions.

Construction of FSS screens coated with ferrite Ba(MnTi)Fe10O19 to implement broadband microwave absorbers is presented in this paper. The decrement method is used to measure the reflective response of the microwave absorber. Both reflectivity and absorption representations recognize the characterization of microwave absorbers for the X‐band. Two types of FSS screens, a square‐lattice screen and an equilateral‐triangle‐lattice screen, are introduced to obtain better bandwidth and absorption in this study. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 41: 323–326, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20131