In this paper, an ultra-wideband (UWB) antenna with symmetric open slots is proposed. The symmetric open slots and the U-shaped feeding line are introduced for obtaining the symmetrical radiation property and the lower cross-polarization level. By using the U-shaped feeding line to feed the symmetric open slots in parallel, four resonances are excited by the different effective resonant length of the open slots and form a wideband, which locates at 3.1-10.8 GHz. The measured results show that the stable radiation patterns and the low cross-polarization level are obtained in the operating band, which shows that the proposed antenna is a good candidate for UWB applications.

A novel spiral stacked thin film transformer was designed based on Si IC technology in this paper. And also, the stacked air core and ferrite core thin film transformers with different turns ratio were prepareed. Then, the S-parameter performance of these two kinds of transformers were measured. The measurement results show that the magnetic core thin film transformer has a better electronic transmission performance. It obtains maximum transmission efficiency 93.7% at the frequency range from 10MHz to 20GHz, and the air core transformer obtains maximum 89% at the same frequency range. Many testings show that ferrite core thin film transformer with turns ratio 1:1 can obtain the transmission efficiency over 60% at the frequency range from 2GHz to 16GHz.

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We research the new thin film transformer equivalent circuit modeling, simulate and modify the traditional estimate formula of the transformer equivalent circuit parameters, in order to attain the automatic extraction of thin film transformer parameters. This paper used MATLAB and Agilent ADS on the thin film transformers for the S parameter simulation. The simulation results show the estimation has better accurate and universal, it also shows the effect of different number of turns and thin film materials on the properties of thin film transformer.

A dual-band low-profile substrate integrated waveguide (SIW) dual-dumbbell-shaped-slot-fed (DDSSF) patch antenna is presented in this letter. The antenna is designed using the dual-dumbbell-slot feeding structure in SIW and two patches to radiate. And it achieves two passbands by exciting two modes of dual dumbbell-shaped slots(DDSSs). The first impedance bandwidth is 4.1%, the second one is 10.0% and gains up to 6.7 dBi and 7.4 dBi, respectively. Furthermore, the two bands can be separated from each other and and the cross-polarization level is below-30 dB. The simulation and measurement results of the proposed antenna are in good agreements. key words: dual-wide-band, low cross-polarization, dumbbell-shaped slot, substrate integrated waveguide (SIW) Classification: XYZ (choose one from Table II) This article has been accepted and published on J-STAGE in advance of copyediting. Content is final as presented.