Wide band amplifiers

A distributed amplifier including a plurality of amplifying devices having their individual control terminals connected to different points along an input filter line which has a predetermined passband, and the output terminals of the amplifying devices being connected to different points along on an output filter line which has an output load at one end and has a predetermined passband which includes a band of frequencies which is alos included in the passband of the input filter line, said points along the output filter line being so chosen that delays between said output terminals are substantially the same as the delays between the corresponding control terminals, and shunt arms in said filter lines being constituted at least in part by internal capacitances of the amplifying device;

• said amplifier further comprising a termination impedance connected to the other end of said output filter line, and said output filter line being substantially wholly reactive and being provided with a portion over which its impedance is tapered so as to constitute a wide band multiple quarter wave impedance transformer providing an impedance match between said output load at one end of said output filter line and said termination impedance at said other end of said output filter line.