Patent ID: 6094588
Filing Date: 2000-07-25
Classification: H01P,Y10S

Abstract:
A radar apparatus comprising:a antenna structure for transmitting and receiving radar signals;a preselector filter stage coupled to the antenna structure;a radio frequency amplifying and downconverting subsystem coupled to the preselector filter stage;a computer system for controlling the operation of the antenna structure and for controlling the application of current pulses to the ferrite structure of the preselector filter state to provide latching control of the ferrite permeability with remanent magnetization and, thereby, to control a pass frequency of the preselector filter stage; andwherein the preselector filter stage includes a planar, tunable microwave filter including,an elongated stripline ferrite substrate structure having a predetermined length and including first and second ferrite layers;a plurality of discrete elongated high-temperature superconductor (HTS) strips of predetermined length, disposed between said first and second ferrite layers, said strips being substantially parallel to each other and mutually staggered in a lengthwise direction along the length of the substrate structure;two of the HTS strips being respectively disposed for input and output connections;at least one of the ferrite layers being structured to provide connection access to the two HTS strips;a latching field coil structure coupled to the ferrite substrate structure, being operable to carry the current pulses, thereby generating magnetic flux in the ferrite substrate structure along magnetic circuitry which extends along the HTS strips and within the field coil structure;whereby the filter tunes the operation of the radar apparatus to the pass frequency which is determined by the permeability of the ferrite substrate structure with remanent magnetization as controlled by the amplitude of the current pulse.