Abstract: An electronic device includes a touch screen, a memory module, a dividing module, an identifying module, a sorting module, and a driving module. The memory module saves multimedia files (MFs). Each MF has four tags, each tag corresponds to a category. The dividing module drives the touch screen to display areas that makes up a grid. The grid has reference lines: a horizontal line, a vertical line, a first diagonal line, and a second diagonal line. The identifying module identifies a vector of a user's slide on the touch screen that is substantially parallel to a reference line. The sorting module receives the vector identified by the identifying module and generates a list making up of the tags of the same category that corresponds to the vector. The driving module reads the list and drives the areas corresponding to the vector to display the tags of the list.

Abstract: A wide band antenna includes a radiation element, a ground surface, a dielectric element, and a RF connector. The radiation element is connected to the ground element and includes a first radiation part and a second radiation part. The first radiation part includes at least one slit for obtaining low frequency-bands. The second radiation part is for obtaining high frequency-bands. The dielectric element supports and spaces the radiation element and the ground element. The RF connector is connected to the second part of the antenna and the ground element.

Abstract: A circuit board includes a wiring layer, a first electronic component, a second electronic component, and a pad matrix. The first electronic component is mounted on the wiring layer and includes a number of first terminals. The second electronic component is mounted on the wiring layer and includes a number of second terminals corresponding to the first terminals. The pad matrix is formed on the wiring layer. The pad matrix includes a number of pads, each two adjacent pads have one pad electrically connected to a first terminal and the other pad electrically connected to a second terminal.

Abstract: A navigation device includes a transceiver, a timer, an angle detector, and a processor. The transceiver is for projecting a detecting signal and receiving the detecting signal reflected from an obstacle in front of the transceiver. The timer is for calculating a time interval between projecting the detecting signal and receiving the detecting signal reflected from the obstacle. The angle detector is for detecting a projecting angle of the detecting signal projected from the transceiver with respect to the vertical direction. The processor is for calculating a horizontal distance to the obstacle according to a velocity of the detecting signal, the time interval, and the projecting angle.