Abstract: A dielectric filter can be miniaturized. A dielectric filter comprised of a plurality of dielectric resonators (R.sub.1), (R.sub.2) having a dielectric block (11) with an outer conductor (12) and in which a plurality of through-holes (13), (13) bored through the dielectric block (11) and inner conductors (14) provided within the plurality of through-holes (13), (13) so as to be electrically connected on their one end faces to said outer conductor (12). Recesses (15) are formed on the other end faces of the plurality of through-holes (13) of the dielectric block (11), and electrodes (16) are formed within the recesses (15) so as to communicate with the inner conductors (14) to thereby construct an additional capacitance (Cp).

Abstract: A short-distance communication antenna can satisfactorily transmit and receive an information signal within a regulation range of the radio law. Also, the short-distance communication antenna provided on a card reader/writer enables the card reader/writer to communicate with a non-contacting information card without being limited by the direction of the non-contacting information card upon reception. This short-distance communication antenna includes a plurality of magnetic poles disposed on a magnetic member and to and from which a magnetic flux is transmitted and received, and a coil for transmitting or transmitting and receiving the information signal mounted on at least one of the magnetic poles. Further, the short-distance communication antenna includes a housing having an aperture to and from which a magnetic flux is transmitted and received, and a coil for transmitting or transmitting and receiving the information signal mounted on said housing.