Seiji Hidaka

Noise design of active feedback resonator BEF

It is shown that, in a filter design system which introduces noise temperature into the active feedback resonator (AFR), the AFR band elimination filter (BEF) can be designed using techniques for the conventional passive BEF. In this system, the passive BEF circuit used for electrical design is also useful for the noise analysis of the AFR BEF. This analysis reveals that the noise figure (NF) value of the AFR BEF can be calculated from the noise temperatures of AFRs. The optimum NF value is obtained by minimizing these noise temperatures. The noise design of a three-pole AFR BEF is discussed. It is found that the observed NF of the three-pole AFR BEF agrees well with the theoretical values deduced from the designed S-parameters and the observed noise temperatures of the AFRs. >

Low profile filter using open disk dual mode dielectric resonators for microcellular base station

This paper present a low profile bandpass filter using open disk dual mode dielectric resonators for microcellular base stations. The resonator consists of two dielectric disks in a cylindrical cavity, and the torus electrode increases the unloaded Q of the resonator. An equivalent circuit consisting of ring shaped transmission line with electrical length of 2? represents the dual mode resonator. A multi-pole bandpass filter can be designed by the Chebysheff type deign method. A 6-pole bandpass filter with the center frequency of 947.5 MHz and insertion loss of 0.7dB is fabricated. Measured response of the filter agrees with the simulated one. The dimensions of the filter are 158×54×23.5 mm.

Application of HTS / Dielectric Multilayered Thin Films for Microwave Devices

A new concept of resonator with an electrode structure consisting of YBa2Cu3O7-δ (YBCO)/MgO multilayered films has been proposed [1]. Toward its realization of this concept, in the present study, epitaxial growth of YBCO / MgO / YBCO trilayered film on LaA1O3 (100) substrate is obtained and its properties are compared with bi- and mono-layered films. The monolayer YBCO films show a good transport and microwave properties and a crystalline quality. The quality of the crystal structure of the film tended to degrade with increasing the number of layer.