Abstract: Provided is an electromagnetic wave transmission sheet having a mesh-shaped electrode. The sheet has a length of width in a direction vertical to the propagation direction of the transmitted electromagnetic wave which length is substantially identical to half of the wavelength of the transmitted electromagnetic wave multiplied by a natural number so that a resonance state is obtained in the vertical direction. It is preferable that the sheet have an electromagnetic wave absorbing medium for reducing reflection of the transmitted electromagnetic wave in the propagation direction, so as to eliminate the need of an electromagnetic wave absorbing medium for reducing reflection in the direction vertical to the propagation direction of the transmitted electromagnetic wave.

Abstract: A communication system comprises a signal carrying apparatus having a first conductor portion (111) of which external shape is sheet-like and which serves as a conductor and a second conductor portion (121), and an interface device having a first electrode (1211) and a second electrode (1222) located near the first conductor portion (111), the normalized reactance derived from the reactance component of the sheet impedance in the signal carrying apparatus is not extremely smaller than 1, and the normalized distance derived from a distance between the signal carrying apparatus and the interface device made closer to substantially equal to 1 or less for transmitting the electromagnetic field in the leak region (141) between the signal carrying apparatus and the interface device and in the interval region (131) between the external shape of the first conductor portion (111) and the external shape of the second conductor portion (121).

Abstract: A signal carrying apparatus (101) for transmitting a signal by variation of electromagnetic field comprises a meshed first conductor portion (111) which serves as a conductor in the frequency band of the electromagnetic field, and a second conductor portion (121) of which external shape is sheet-like and which serves as a conductor in the frequency band of the electromagnetic field and arranged substantially in parallel with the first conductor portion (111). In the interval region (131) between the external shape of the first conductor portion (111) and the external portion of the second conductor portion (121), and in the planar leak region (141) located oppositely to the interval region (131) across the external shape of the first conductor portion (111), the electromagnetic field propagating in that frequency band has a strength attenuating exponentially with the distance from the external shape of the first conductor portion (111) in the leak region (141).

Abstract: In a communication unit 100, a ground layer section 101 which is a sheet-like conductive material and a power-source layer section 102 which is a sheet-like conductive material are laid out in such a way that their one sides face each other, a voltage is applied in such a way that the power-source layer section 102 has a predetermined reference electric potential to the ground layer section 101, a plurality of conductive layer sections 103 which are sheet-like conductive materials are laid out between the ground layer section 101 and the power-source layer section 102, each conductive layer section 103 and the power-source layer section 102 are coupled together by a pull resistor section 104, a transmission communication element transmits a signal by changing the electric potential of the conductive layer section 103 connected to that communication element with respect to the ground layer section 101, and a reception communication element receives the signal by directly or indirectly detecting a change in ele