Showing papers on "Active antenna published in 1987"

Transmit-receive means for phased-array active antenna system using rf redundancy

Abstract: An improved phased-array active antenna transmit-receive means utilizing a multiplicity of individual transmit-receive cells positioned in an array format upon a common wafer of semiconductor material. Each transmit-receive cell, comprises a multiplicity of redundant, integrated circuit, electronic devices implanted upon the common semiconductor substrate. The transmit-receive cells utilize novel mitered mechanical switches to permanently interconnect individual electronic devices into either transmit or receive circuits during the fabrication and test of the transmit-receive cells. Radio frequency and direct current input and output vias formed from a novel metal evaportion technique connect the devices upon the surface of the common semiconductor wafer to underlying, insulated direct current distribution circuits and a radio frequency manifold. This array of improved phased-array active antenna transmit-receive means comprised of transmit-receive cells sharing common central processing means, logic control and heat dissipation means results in a significant reduction in the size and weight of the standard phased-array active antenna system. This significant reduction in antenna system size and weight is very important in broad band electronic countermeasure systems or narrow band phased array active antenna radar systems as used in advanced tactical fighters, or space applications.

Film type active t.v. antenna

Abstract: The utility model discloses an active television receiving antenna of which appearance is like an indoor light fitting. The utility model is characterized in that the part of the antenna is a light shade and is made by metal thin films. Both faces of the light shade are attached with protecting layers. The active amplifier is arranged in a little box which is under the light seat of the light fitting. An illumination light which is connected with an incoming line of a power supply in parallel with small wattage is arranged on the light seat. The light is turned on when the active antenna is working. The active antenna is suitable to the areas where the television signal is weak and the phenomena of ghost are serious. The utility model makes the image of the television receiver clear, lowers the cost, and has the function of protecting the eyes of the television audiences.

Optimal design of multiply fed dipole antennas

Abstract: The gain of a mulitply fed dipole antenna of length L , small radius a and arbitrary locations of feed voltages along the antenna is computed using the well-known moment method. An optimization routine is then employed to study the possibility of maximizing the gain in a specified angular direction and minimizing it at other directions for any given number of excitations and antenna length in order to determine the optimum complex values and location of each source. The results are presented in tables and graphs for a wide range of antenna length and number of feeds. It is shown that both the gain and beamwidth are improved by this technique at the expense of appearance of new sidelobes and requirement to design a more complicated feed network. The Fourier series expansion method is extended in order to determine the gain of a multiply fed wire antenna, and the results for the radiation pattern show good agreement with those based on the moment method.

Radio control device for locking/unlocking of automobile door

Abstract: PURPOSE:To attain the low cost and to keep the beautiful external appearance by providing a distributor to an active antenna, inputting a high frequency signal from a transmitter to a receiver by means of the distributor so as to apply locking/unlocking thereby eliminating the need for an exclusive remote control antenna CONSTITUTION:A higher frequency than a radio frequency band or a telephone transmission/reception frequency band is selected for the carrier frequency of a remote control transmitter 5 and a pass word is sent A distributor 21 is provided to either a radio reception antenna 2 or a telephone transmission/ reception antenna 3 in an automobile 1 A radio broadcast signal or a telephone transmission/reception signal is inputted from the distributor 21 to a radio receiver or telephone transmission/reception device 22 Further, a high frequency signal from the transmitter 5 is inputted to a tuning circuit 13 of the receiver 20 A pass word is set in advance to a decoder 15 by a data code selector 16 and when the pass word from the transmitter 5 is coincident, a control circuit 17 activates an actuator 18 to apply locking or unlocking