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 dual-band antenna includes a RF connector, a radiation element, and a ground surface. The RF connector is connected to a RF receiver. The radiation element includes a first radiation element and a second radiation element. The first radiation element and the second radiation element are both connected to the RF connector. The RF connector is connected to the ground surface.

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.

Abstract: A set of electronic frames capable of detecting an external device includes a main frame and an external frame. The main frame includes an R-C circuit with a detecting pin, a resistor coupled to the detecting pin, and a voltage comparator for comparing the potential at the detecting pin and a reference potential. The external frame includes a connecting port coupled to the R-C circuit of the main frame. The connecting port includes an identifying pin coupled to the detecting pin, and an R-C circuit coupled to the identifying pin.