Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
453 words
A frequency combining circuit in the form of a planar transmission circuit and operative in a selected frequency band, said frequency combining circuit comprising: a four-port directional coupler having a coupler input port for receiving a first frequency signal in a first frequency band, a first coupler branch line coupled to said coupler input port, a coupler output port coupled to said first coupler branch line for receiving said first frequency signal from said coupler input port through said first coupler branch line, a coupler forward coupling port coupled to said first coupler branch line for receiving a portion of said first frequency signal, a second coupler branch line coupled to said coupler forward coupling port, and a coupler backward coupling port coupled to said second coupler branch line and also coupled to said first branch line; a first transmission line coupled at one end thereof to said coupler backward coupling port; first filter means coupled to the other end of said first transmission line for receiving a second frequency signal from a signal source, said second frequency signal being in a second frequency band separated from said first frequency band, said first filter means having a filtering property for rejecting said first frequency signal and passing therethrough said second frequency signal to said first transmission line and hence to said coupler backward coupling port, a portion of said second frequency signal being transferred to said coupler output port, and the other portion of said second frequency signal being transferred to said coupler forward coupling port through said second coupler branch line; a second transmission line coupled at one end thereof to said coupler forward coupling port for passing therethrough to the other end thereof said portion of said first frequency signal from said coupler forward coupling port; second filter means coupled to said other end of said second transmission line and having a filtering property for rejecting said first frequency signal and passing therethrough said second frequency signal; and a load to which said second filter means is also coupled, said portion of said first frequency signal passed through said coupler forward coupling port and said second transmission line being rejected by said second filter means and being returned to said coupler forward coupling port through said second transmission line, and said other portion of said second frequency signal passed through said second coupler branch line, said coupler forward coupling port and said second transmission line being passed through said second filter means and being absorbed by said load, and the pass band of said frequency combining circuit for said first frequency signal being varied by varying the length of said first transmission line and the length of said second transmission line.
Claim 2
Dependent Claim
453 words
A frequency combining circuit in the form of a planar transmission circuit and operative in a selected frequency band, said frequency combining circuit comprising: a four-port directional coupler having a coupler input port for receiving a first frequency signal in a first frequency band, a first coupler branch line coupled to said coupler input port, a coupler output port coupled to said first coupler branch line for receiving said first frequency signal from said coupler input port through said first coupler branch line, a coupler forward coupling port coupled to said first coupler branch line for receiving a portion of said first frequency signal, a second coupler branch line coupled to said coupler forward coupling port, and a coupler backward coupling port coupled to said second coupler branch line and also coupled to said first branch line; a first transmission line coupled at one end thereof to said coupler backward coupling port; first filter means coupled to the other end of said first transmission line for receiving a second frequency signal from a signal source, said second frequency signal being in a second frequency band separated from said first frequency band, said first filter means having a filtering property for rejecting said first frequency signal and passing therethrough said second frequency signal to said first transmission line and hence to said coupler backward coupling port, a portion of said second frequency signal being transferred to said coupler output port, and the other portion of said second frequency signal being transferred to said coupler forward coupling port through said second coupler branch line; a second transmission line coupled at one end thereof to said coupler forward coupling port for passing therethrough to the other end thereof said portion of said first frequency signal from said coupler forward coupling port; second filter means coupled to said other end of said second transmission line and having a filtering property for rejecting said first frequency signal and passing therethrough said second frequency signal; and a load to which said second filter means is also coupled, said portion of said first frequency signal passed through said coupler forward coupling port and said second transmission line being rejected by said second filter means and being returned to said coupler forward coupling port through said second transmission line, and said other portion of said second frequency signal passed through said second coupler branch line, said coupler forward coupling port and said second transmission line being passed through said second filter means and being absorbed by said load, and the pass band of said frequency combining circuit for said first frequency signal being varied by varying the length of said first transmission line and the length of said second transmission line.
Claim 3
Dependent Claim
25 words
A frequency combining circuit as claimed in claim 1 wherein said coupler branch lines of said directional coupler are a parallel coupled microstrip line pair.
Claim 4
Dependent Claim
50 words
A frequency combining circuit as claimed in claim 2 wherein said first and second transmission lines have lengths for preventing a frequency signal outside both said first and second frequency bands and applied to said coupler input port for the first frequency signal from appearing at said coupler output port.
Claim 5
Dependent Claim
22 words
A frequency combining circuit as claimed in claim 1 wherein said coupler branch lines of said directional coupler are hybrid branch lines.
Claim 6
Dependent Claim
50 words
A frequency combining circuit as claimed in claim 4 wherein said first and second transmission lines have lengths for preventing a frequency signal outside both said first and second frequency bands and applied to said coupler input port for the first frequency signal from appearing at said coupler output port.