This article presents a miniaturized dual‐mode bandpass filter (BPF) with two transmission zeros and low insertion‐loss using crossed slotted patch resonator. The BPF is mainly formed by a λ/2 patch resonator which is a pair of crossed slots with unequal widths is embedded in the center. By tuning the perturbation element, which resulted from the unequal slot widths along the diagonal, two resonant modes are excited and a pair of transmission zeros are generated to improve the selectivity of the BPF performance. The proposed filter at center frequency (f0) of 1.55 GHz has very good measured characteristics including the bandwidth of 1.49–1.62 GHz (3‐dB fractional bandwidth of 8.4%), low insertion loss of 1.74 ± 0.35 dB. The measured filter performance is in good agreement with the simulated response. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 741–744, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23219

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In this letter, a novel dual‐mode bandpass filter (BPF) using stepped impedance resonators (SIRs) for simultaneous low insertion‐loss and wide passband has been designed. This novel wideband dual‐mode BPF is formed by a microstrip square ring resonator with direct‐connected orthogonal feed lines, and two impedance steps as perturbations. By varying the impedance ratio (K) of the SIRs, the wideband bandwidth can be tuned with more freedoms. The design procedure using the analysis of even and odd mode is described in this paper. The wideband BPF with relative bandwidth of 76.5% is simulated using the full wave electromagnetic simulation, and then fabricated and measured using the network analyzer. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 1104–1107, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23281

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The (100)-oriented aluminum nitride (AlN) thin films were well deposited onto p-type Si substrate by radio frequency (RF) magnetron sputtering method. The optimal deposition parameters were the RF power of 350 W, chamber pressure of 9 mTorr, and nitrogen concentration of 50%. Regarding the physical properties, the microstructure of as-deposited (002)- and (100)-oriented AlN thin films were obtained and compared by XRD patterns and TEM images. For electrical properties analysis, we found that the memory windows of (100)-oriented AlN thin films are better than those of (002)-oriented thin films. Besides, the interface and interaction between the silicon and (100)-oriented AlN thin films was serious important problem. Finally, the current transport models of the as-deposited and annealed (100)-oriented AlN thin films were also discussed. From the results, we suggested and investigated that large memory window of the annealed (100)-oriented AlN thin films was induced by many dipoles and large electric field applied.