Patents by Inventor Sek L. Chan

Sek L. Chan has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Antenna switch for transmit-receive operation using relays and diodes
    Patent number: 5060293
    Abstract: A four port antenna switch (300) for switching a receive port (320) and a transmit port (310) between a remote antenna port (330) and a standard antenna port (340) is provided. The switching actions of the receive port (320) between the remote antenna port (330) and the standard antenna port (340) is provided by a relay (350) under the control of a relay controller (352, 354, 400). The switching of the transmit port (310) between the standard antenna port (340) and the remote antenna port (330) is provided by diode switches (360, 370) under the control of diode switch controllers (332, 324, 312, 314, 400). The switching actions of the relay (350) and the diode switches (370, and 360) is complementary to each other, wherein sufficient isolation between the receive port and the transmit port is provided. In this arrangement, a low power relay may be used because the relay only switches low level received signals, and the high power transmit signals are switched by the pins.
    Type: Grant
    Filed: October 20, 1989
    Date of Patent: October 22, 1991
    Assignee: Motorola, Inc.
    Inventors: Gee S. Kok, Sek L. Chan, Wan F. Tay, Pek B. Teo, Chacko Prakash, Hock S. Lim