Dielectric resonator, dielectric filter and method of producing the same, filter device combined to a transmit-receive antenna and communication apparatus using the same

摘要

A dielectric resonator includes a pair of dielectric substrates opposed to each other and resonator electrodes disposed between the pair of dielectric substrates. The resonator electrodes are disposed so as to be brought into contact with major surfaces of the pair of dielectric substrates, and a bonding layer is disposed around the resonator electrodes so as to bond the pair of dielectric substrates. The pair of dielectric substrates have been sintered in advance at sufficiently high temperature which is a dielectric having an fQ value at 1 GHz in the range of 3x10³ to 1x10⁵, and then achieve a high Q value as a filter. The pair of the substrates are provided with a surface roughness of a range of 0.1 to 2.0 mum, and flatness of 10 mum or less between both ends thereof to bring the resonant electrodes in close contact with the surfaces of the substrate. Such ceramic filters are used comfortably for a filter connecting a transmit-receive antenna to a transmitter and receiver, which can provide communication equipment having a good high frequency performance for cellular telephone systems.