This paper describes the outline of recent standardization activities for Radio on Fiber (RoF) transmitter by IEC TC103/WG5. RoF transmitter consists of optical fibers, electrical to optical (E/O) converter, and optical to electrical (O/E) converter. IEC TC103/WG5 is working on standardization on measurement method of E/O and O/E devices, and technical specification of RoF transmitter. This paper overviews those standardization activities which are being developed by TC103/WG5 as well as the National Committee of WG5.

Enclosures of electronic equipment are an important item to suppress the unwanted emissions from digital processing circuits. However, the shielding effect at high frequencies is decreased by slits and apertures of the enclosures. The method for evaluating shielding effect of enclosures above 1 GHz was investigated in this paper. A disc-cone antenna operated by an O/E converter was developed and the radiation property was calculated by the method of moment. The results indicated that the deviation between the calculation and the measurement value was within 3 dB in the case of that the antenna is operated in the frequency range from 1 GHz to 10 GHz. The antenna was placed in the enclosure model constructed with wire meshes and the shielding effects were calculated and measured from 1 GHz to 3 GHz. The results showed that the tendency of the calculated value closely agreed with that of the measured value. Using the antenna, the shielding effect of the PC cases were investigated from 1 GHz to 8 GHz. The results indicated that the shielding effect is decreased in proportion with the increase of frequency, and the careful design was important to maintain the shielding effect in this frequency range.