Understanding the relationship between the surface conditions and giant magneto-impedance (GMI) in Co-rich melt-extracted microwires is key to optimizing their magnetic responses for magnetic sensor applications. The surface magnetic domain structure (SMDS) parameters of ~45 μm diameter Co69.25Fe4.25Si13B13.5-xZrx (x = 0, 1, 2, 3) microwires, including the magnetic domain period (d) and surface roughness (Rq) as extracted from the magnetic force microscopy (MFM) images, have been correlated with GMI in the range 1–1000 MHz. It was found that substitution of B with 1 at. % Zr increased d of the base alloy from 729 to 740 nm while retaining Rq from ~1 nm to ~3 nm. A tremendous impact on the GMI ratio was found, increasing the ratio from ~360% to ~490% at an operating frequency of 40 MHz. Further substitution with Zr decreased the high frequency GMI ratio, which can be understood by the significant increase in surface roughness evident by force microscopy. This study demonstrates the application of the domain period and surface roughness found by force microscopy to the interpretation of the GMI in Co-rich microwires.

A novel wideband digital polarization synthesis method is presented here. The method is based on the definition of antenna polarization and both simulated and measured antenna patterns. A mathematical formulation is used to determine the synthesis coefficients. Any state of polarization (elliptical, circular, and linear) can be synthesized theoretically. Here, we mainly focus on the method for synthesizing linearly polarized antennas into circularly polarized antennas. There is no restriction regarding the array geometry or element patterns. The method can yield pure circularly polarized antenna patterns within the whole working band. The synthesized circularly polarized antennas are then used to receive circularly polarized signals. The method can provide more accurate polarized data for wideband solar radio observations and other systems that require accurate polarization measurements.

Abstract-Based on the theory of Babinet's principle, a type of dual-polarized antenna working on C band is designed using complementary structures. The structures comprise a wire loop antenna and a slot loop antenna, which is complemented and fed by coaxial lines. A ground is placed to improve the front-to-back ratio of the antenna. The performance of the antenna is hereinafter studied experimentally, followed by the implementation of a prototype antenna. Its stable and symmetric radiation patterns are obtained within the frequency of 4.9 GHz∼5.1 GHz, and the port isolation is less than −24 dB. The measured results coincide with the simulated ones. This explains the feasibility of the proposed dual-polarized antenna.

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