Patent ID: 6300814
Filing Date: 2001-10-09
Classification: H03H

Abstract:
A step attenuator, comprising:first and second resistors connected in series between an input terminal supplied with an input signal and an output terminal;a first switch connected between said input terminal and said output terminal in parallel to said first and second resistors; anda shunt circuit including a transmission line having a first end continuously connected to a joint of said first and second resistors and a second end, and a third resistor and a second switch connected in parallel between the second end of said transmission line and a reference potential point;said transmission line being .lambda./4-.alpha.(0.ltoreq..alpha..ltoreq..lambda./16) in length, where .lambda. denotes the wave-length of said input signal;said first and second switches being turned ON in a through-mode so that said shunt circuit represents such a first impedance that allows said input signal to pass through said first switch and appear at said output terminal; andsaid first and second switches being turned OFF in a attenuation-mode so that said shunt circuit represents such a second impedance that is lower than said first impedance to allow a part of said input signal to flow through said shunt circuit into said reference potential point.