Disclosed herein is a functional tunable multichannel filter which is capable of adjusting channel spacing andor a wavelength location using polarization controllers. A rotating body has a permanent magnet, a first magnetization member and a second magnetization member. The RFID device includes a transceiver that uses the antenna to carry on communications with an RFID reader. At least one secondary imaging sensor is disposed along the housing, adjacent to the first imaging sensor. The load-enhancing device comprises a stator and a rotor arranged in such as way as to achieve a magnetic thrust load capacity enhancement by employing a number of permanent magnets, which produce an attracting force of an expulsing force between the rotor and the stator. In addition, certain electronic components may be shared by the hard disk controller and player electronics, thus further reducing the cost and size of the portable device.