Abstract: A compact printed antenna includes a substrate and a printed circuit on the substrate. The printed circuit includes a ground metal, a helical metal, a short circuit leg and a feeding leg. The ground metal has a feeding structure. The helical metal includes a plurality of conductive apertures to connect a plurality of metal strips to form a flat helical structure. The helical metal is parallel with the ground metal and has a short circuit end and an open circuit end to form an open circuit-short circuit structure. The short circuit end connects the ground metal through the short circuit leg. The feeding leg is extended outwards from a selected location on the helical metal to further connect a matching circuit. By providing the compact printed antenna, the flat helical structure of the helical metal can be shrunk in size, an inductance to allow the antenna making desired adjustment for the input impedance can be generated, and the adjustment freedom upon coupled impedance for the antenna can be increased.

Abstract: An improved planar inverted F-type antenna comprises a metal ground plane having a feeding metal bore formed thereon, and a flat metal plate in parallel with the metal ground plane. The flat metal plate further includes an open circuit end and a short circuit end and provides a feeding leg to pass through the feeding metal bore. The short circuit end connects the metal ground plane through a short circuit leg. The distance between the open circuit end and short circuit end of the flat metal plate is proximate a quarter of wavelengths. The flat metal plate is formed as an open-short circuit trapezoid-shaped structure. The trapezoid-shaped structure increases operative bandwidth of the antenna.

Abstract: An indented planar inverted F-type antenna apparatus comprises a metal ground plane having a feeding metal bore formed thereon and a crenellated metal in parallel with the metal ground plane. The crenellated metal further has an open-circuit end and a short-circuit end. The short-circuit end can connect with the metal ground plane through a short-circuit leg. Further, the crenellated metal can include a feeding leg for extending to pass through the feeding metal bore. By providing the crenellated structure of the crenellated metal, the size of the antenna can be reduced and an irregular electric field can be generated between the crenellated metal and the metal ground so that various frequencies of signals can be obtained and also operating frequency band of the antenna can be extended.

Abstract: An antenna of the wireless LAN card includes a body with an antenna on one side, a connecting base is on one side of the external wireless LAN card, a pivot pin is on top of the connecting base; a cross pivot wraps the pivot pin. The cross pivot composes of a tube with a pintle on both sides. A ball tip is on the bottom of the antenna, a hole is inside the ball tip, a joint hole each is on both sides of the hole. The two pintles of the cross pivot are inserted into the joint hole of the ball tip of the antenna. The structure makes the direction of the antenna of the wireless LAN card adjustable for best signal transmission and receiving result.

Abstract: A connecting apparatus for interconnection between serial data transmission devices, includes a DTE/DCE selector switch, a signal level converter, a single chip CMOS CPU and the RJ45 telephone bus cables, wherein the CPU controls the receiving and transmitting modes between the signal lines of the RS232 interface and the RJ45 telephone bus cables and also controls data transmission time so as to prevent the connected serial data transmission devices from sending out data at a time. The connecting apparatus can be connected with personal computers, serial printers, plotters or modems in series for data transmission to and from one another, and therefore jumper cables between either two data transmission devices are eliminated. Furthermore two connecting apparatus may be interconnected through RJ45 telephone bus cables, therefore it is easy to install and to expand data transmission devices.