| 摘要 |
PURPOSE:To attain broad band of a microwave band phase shifter by providing a transmission line having a length representing the impedance viewed from the 2nd and 3rd terminals toward a varactor diode to be zero or infinite between both the terminals and the diode. CONSTITUTION:Transmission lines 4, 5 having a length representing the impedance viewing the varactor diode to be zero are inserted between the 2nd and 3rd terminals of the branch type hybrid 1 and the varactor diodes 2, 3. Denoting the frequency of an input wave as 5GHz, the capacitance C of the diodes as 1.0pf being the midpoint of the variable range, then the free space length of the transmission lines is 5.4mm. In obtaining the relation of the relative phase versus frequency of a microwave band phase shifter, the maximum phase shift in changing the capacitance C of the diodes from 0.6pf to 1.4pf is nearly 67 deg. at nearly 4.0GHz and the minimum phase shift is nearly 44 deg. at nearly 5.2GHz. The frequency deviation of the phase shift is 23 deg. and it is compressed to nearly 1/3.
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