Influence of hydrogen on magnetic properties of soft magnetic amorphous alloys
The influence of electrolytic hydrogenation on the magnetic properties of three different kinds of amorphous alloys has been investigated. The alloys studied were Fe/sub 83.3/Si/sub 3.5/B/sub 11.2/C/sub 2/, Fe/sub 38/Ni/sub 38/Mo/sub 2/Si/sub 8/B/sub 14/, and (Co/sub 86/Fe/sub 5/Cr/sub 9/)/sub 75/Si/sub 10/B/sub 15/. The experimental results showed that after hydrogenation the samples became very brittle and the soft magnetic properties degraded dramatically, but saturation magnetization sigma /sub s/ and average hyperfine field increased markedly. As hydrogen evolved from the charged samples which were placed in air at room temperature, the magnetic properties, toughness, and average hyperfine field were gradually recovered. >
Effect of hydrogen on the magnetic behavior of CoFeCrSiB amorphous alloys
Alloying with Fe caused a non-monotonic change in the soft magnetic properties of Co71−XFeXCr7Si8B14 alloys. Hydrogenation caused a progressive deterioration in the soft magnetic properties. The differences in the response of the alloys is possibly due to a non-systematic variation in the inter-atomic exchange interactions which modulates the dipole moment, and due to introduction of internal stresses on hydrogen charging.
Compact Circularly Polarized Composite Cavity-Backed Crossed Dipole for GPS Applications
In this paper, we present a circularly polarized (CP) composite cavity-backed crossed dipole antenna for global positioning system (GPS) applications. We produce the CP radiation by crossing two dipoles through a 90° phase delay line of a vacant-quarter printed ring, which also has a broadband impedance matching characteristic. Two techniques, insertion of meander lines in the dipole arm and arrowhead-shaped trace at its end, are employed to reduce the sizes of the primary radiation element. The compact radiator is backed by a cavity reflector to achieve a wide CP radiation beamwidth. The proposed antenna exhibits a measured bandwidth of 1.450～1.656 GHz for a voltage standing wave ratio (VSWR) < 2 and 1.555～1.605 GHz for AR < 3-dB. At 1.575 GHz, the antenna has a gain of 7 dBic, a frontto-back ratio of 27 dB, AR of 1.18 dB, and 3-dB AR beamwidths of 130° and 132° in the x-z and y-z planes, respectively.