The present invention comprises a substantially omnidirectional antenna with minimal gain variation over the 360 degree azimuth. A plurality of biconical antenna elements are stacked, wherein a feed line passes through the center of the biconical antenna elements. The feed line is designed to provide the proper quantity of power to each biconical antenna element without the use of a power divider. Each biconical antenna element is formed by two truncated flared apart reflecting surfaces. Each biconical antenna element is attached to a nonconductive collar above and below.

Collinear coaxial slot-fed-biconical array antenna

A low radar cross-section monocone antenna is provided with an ultra-wide bandwidth in the microwave region of the electromagnetic spectrum running from 1 gigahertz to 18 gigahertz by decreasing the low frequency cutoff through enlarging the overall dimensions of the cone while at the same time maintaining the base diameter of the apex of the cone to the initially-set dimension that establishes the high frequency cutoff of the antenna. The apex of this cone that serves as its feed point has a base diameter that results in the wide bandwidth, with the monocone antenna having a 5 dBi gain and omnidirectional coverage.

Compact low RCS ultra-wide bandwidth conical monopole antenna

An electronic system including a connector (J1) for an external device such as an infrared receiver (12) includes a signal processor (20), responsive to the infrared receiver and an electrical isolation device such as an optocoupler (18), coupled between the connector (J1) and the signal processor (20). Such a system can further include electromagnetic interference suppression circuitry such as a ferrite bead (14), capacitors (C1, C2) coupled to the earth potential, coupled between the connector (J1) and the optocoupler (18). Such a system can also further include electrostatic discharge suppression circuitry resistors (R1, R2) coupled between the connector (J1) and the optocoupler (18). Application: infrared remote control devices.

Electrical isolation between ir receiver and further electronic circuits

A driver circuit can be used to drive a matrix display device, such as a liquid crystal display, that includes a plurality of pixels 16 disposed in rows 12 and columns 14. A first switch 328 has a current path coupled between a high voltage node (e.g., VS) and a group of pixels 16. As an example, the group of pixels 16 can be a row 12 or a column 14. A second switch 326 has a current path coupled between a low voltage node (e.g., ground) the group of pixels 16. A third switch 322 has a current path coupled between an inductive storage element 34 and the group of pixels. The inductive storage element 34 is coupled to an intermediate voltage node (e.g., VS/2) with a voltage between the voltage at the high voltage node and the voltage at the low voltage node.

Low power drivers for liquid crystal display technologies

A biconical antenna includes an entry conic having an entry base opposite an entry vertex and a termination conic having a termination base opposite a termination vertex. The entry and termination conics share substantially the same axis and the entry vertex is adjacent the termination vertex. The transmission line is received by the entry conic and terminated in the termination conic. Together, the entry conic and the termination conic phase correct energy emanating from the transmission line. Another embodiment of the antenna comprises an entry conic having at least two sub-conics and a termination conic having at least two sub-conics. Each of the sub-conics having an integer multiple of a half-angle. The biconical antenna may also include a multi-conductor transmission line, wherein the biconical antennas are arranged in a co-linear relationship. Each of the multi-conductors is coupled to at least one of the plurality of biconical antennas. The biconical antennas may also be constructed on a circuit board substrate.

Wide band biconical antennas with an integrated matching system

A ferrite sleeve or bead either in round configuration or square or rectangular configuration and either whole or split is employed as a means for reducing radiation emissions associated with a computer or the like data processing system. The ferrite system is disposed over the I/O cable either over a segment thereof or along the length thereof and in one embodiment is in the form of one or more ferrite beads that may be associated with wires internal to the data processing system. In a further embodiment of the invention the ferrite sleeve may be replaced by an equivalent circuit network comprising a parallel inductor and resistor in which the inductor is wound over a resistive core. The ferrite sleeve is dimensioned to have an impedance at the operating frequency greater than the signal cable conductor means radiation resistance, thus establishing a voltage divider circuit between the impedance of the ferrite sleeve and the radiation resistance, to thus reduce emissions due in particular to common mode noise.

Electromagnetic emission control system

A reference antenna construction preferably employing a biconical antenna in combination with a balanced to unbalanced transformer or balun adapted to provide proper matching and operation over a broad frequency range. The reference antenna is used to calibrate other antennas. A ferrite sleeve is preferably used over the balun to reduce unbalanced currents flowing in the shield and to improve performance. A tool is described that allows fast and accurate construction of the balun by providing precise severing of the center conductor.

Reference antennas for emission detection

A circuit is described for substantially reducing the level of radiation from another circuit such as a clock circuit that might be used in a computing device. By maintaining the current drawn by the clock driver from the power supply at a constant level, the amount of radiation is lowered. If all currents drawn can be controlled so as not to change as the clocking occurs, then radiation from the clock is essentially eliminated.

Glen Dash

Papers

Electromagnetic emission control system

Reference antennas for emission detection

Circuit for minimizing radiation