Plane Wave Scattering from Infinite Microstrip Arrays on Ferrite Substrates

A full-wave analysis of planewave scattering from an infinite, periodic array of microstrip patches on a ferrite slab under different bias conditions is presented. The magnetic bias field is applied in a direction parallel to the slab. The scattering coefficient which is directly related to the monostatic radar cross section is seen to move around in frequency as the bias field strength changes. This effect indicates that microstrip antennas could be made invisible or to hide in frequency when not in transmitting or receiving mode. The bias field could be applied when the antenna is not transmitting but one wishes to hide it

The Effects of Perceived Parental Expectations on Chinese Children's Mathematics Performance

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Miniature Microstrip Antenna With a Partially Filled High-Permittivity Substrate

A new technique to reduce the overall dimension of a microstrip antenna using a partially filled high-permittivity substrate is proposed. The miniaturized microstrip antenna for a repeater system in a mobile communication cellular band (824–894 MHz) is designed with the proposed technique and manufactured with light weight and small size. Comparison between simulations, based on HP HFSS software and measurements are provided

The Longitudinal Effects of STEM Identity and Gender on Flourishing and Achievement in College Physics

Background. Drawing on social identity theory and positive psychology, this study investigated women’s responses to the social environment of physics classrooms. It also investigated STEM identity and gender disparities on academic achievement and flourishing in an undergraduate introductory physics course for STEM majors. 160 undergraduate students enrolled in an introductory physics course were administered a baseline survey with self-report measures on course belonging, physics identification, flourishing, and demographics at the beginning of the course and a post-survey at the end of the academic term. Students also completed force concept inventories and physics course grades were obtained from the registrar. Results. Women reported less course belonging and less physics identification than men. Physics identification and grades evidenced a longitudinal bidirectional relationship for all students (regardless of gender) such that when controlling for baseline physics knowledge: (a) students with higher physics identification were more likely to earn higher grades; and (b) students with higher grades evidenced more physics identification at the end of the term. Men scored higher on the force concept inventory than women, although no gender disparities emerged for course grades. For women, higher physics (versus lower) identification was associated with more positive changes in flourishing over the course of the term. High-identifying men showed the opposite pattern: negative change in flourishing was more strongly associated with high identifiers than low identifiers. Conclusions. Overall, this study underlines gender disparities in physics both in terms of belonging and physics knowledge. It suggests that strong STEM identity may be associated with academic performance and flourishing in undergraduate physics courses at the end of the term, particularly for women. A number of avenues for future research are discussed

The RCS of a Microstrip Antenna on an In-Plane Biased Ferrite Substrate

The numerical solutions for the RCS of a microstrip patch on an in-plane biased ferrite substrate are presented. The peaks in the RCS can be moved with respect to frequency by changing the magnetic bias field. We consider a monostatic RCS with various incident angles and examine all four elements of the cross-section matrix. For the case of an unmagnetized ferrite substrate the cross-polarized RCS components are zero. When the ferrite is magnetized, the cross-polarized RCS components become as significant as do the copolarized RCS components. It is also shown that a loaded patch has the effect of significantly reducing RCS at resonances. The analysis used is based on a full-wave moment method with the exact spectral-domain Green\u27s function

Stacked Multiband Fractal Patch Antennas

In this work, the Sierpinski carpet microstrip patch is modified by stacking iterations to achieve multiband frequency operation and miniaturization

Modified Multiband Sierpinski Gasket Monopole Antennas

We present printed modified Sierpinski triangle and carpet monopole antennas. To reduce the overall size of the Sierpinski gasket antenna, the ground plane is printed on the backside of the substrate. The Sierpinski triangle gasket is made and compared with the modified Sierpinski triangle and carpet or truncated triangle gasket monopole antennas

Radiation and Scattering by Infinite Microstrip Patch Arrays on Anisotropic Substrates

An analysis is presented of an infinite array of printed patches on a grounded anisotropic-dielectric slab. The array is considered as both a transmitter fed by idealized probes and as a scatterer of plane waves. For the transmitter case, the input reflection coefficient versus incident angle is computed for various loads and substrates. The theory in both cases is confirmed by comparing its limit to isotropic cases with previous analyses. The inputs to the analysis are the substrate parameters, the array grid geometry, the patch dimensions including probe position, and the probe load impedance, which is assumed conjugate matched at broadside for the transmit case

DUAL TRIDENT UWB PLANAR ANTENNA WITH BAND NOTCH FOR WLAN

In this paper, a compact microstrip fed ultra-wideband antenna with a band notch characteristic is presented. The proposed antenna consists of two tridents and two uneven split ring resonators. The overall size of the antenna is 26 mm × 24 mm × 1.53 mm. By adding the uneven split ring resonators to the dual trident ultra-wideband antenna, a band notch of 5.05 GHz to 5.9 GHz is achieved. The band notch is adjusted by the size and the split locations of the resonators. CST microwave studios software was used to simulate the design. The measured |S11| (dB) pass band and notch band agree with the simulation within the frequency band from 3.65 GHz to 12.85 GHz