Series connected bit phase shifter having first and second impedance adjusting circuits

1. A bit phase shifter comprising:

a plurality of phase shifters having phase shift amounts and connected in series through connection paths;

a first adjusting circuit provided in said connection path between every adjacent two of said plurality of phase shifters; and

second adjusting circuits provided between an input terminal and a first one of said plurality of phase shifters and between an output terminal and a last one of said plurality of phase shifters,

wherein each said first adjusting circuit comprises a first inductance which attains impedance matching to said adjacent two phase shifters, and

wherein each of said second adjusting circuits comprises,

second inductances which attain impedance matching to the first one and the last one of said plurality of phase shifters, respectively, and

two capacitors connected in series, with a respective one of said second inductances between said two capacitors.

2. The bit phase shifter according to claim 1 , wherein each of said plurality of phase shifters comprises a single pole double throw (SPDT) switch, and

said SPDT switch is of a resonance type or a series shunt type.

3. The bit phase shifter according to claim 2 , wherein an impedance of one of said plurality of phase shifters viewed from a respective one of said connection paths shows a capacitance of 0.01-1.00 pF.

4. The bit phase shifter according to claim 2 , wherein each said SPDT switch comprises a FET (Field effect transistor) connected to a respective one of said connection paths, and each said FET is controlled by applying a voltage equal to or higher than 0 volt to a corresponding gate of each said FET.

5. The bit phase shifter according to claim 4 , wherein each said first adjusting circuit further comprises two capacitors connected in series, wherein said corresponding first inductance is between said two capacitors.

6. The bit phase shifter according to claim 1 , wherein each said second inductance is of a shunt inductor.

7. The bit phase shifter according to claim 1 , wherein each said first inductance is of a shunt inductor.

8. The bit phase shifter according to claim 1 , wherein each said second inductance is about double of each said first inductance.

9. A bit phase shifter comprising:

a plurality of phase shifters having phase shift amounts and connected in series through connection paths;

a first adjusting circuit provided in said connection paths between every adjacent two of said plurality of phase shifters; and

second adjusting circuits provided between an input terminal and a first one of said plurality of phase shifters and between an output terminal and a last one of said plurality of phase shifters,

wherein each said first adjusting circuit comprises,

two first capacitors connected in series, and

a first inductance connected between said two first capacitors and configured to attain impedance matching to said adjacent two phase shifters, and

wherein each of said second adjusting circuits comprises,

two second capacitors connected in series, and

a second inductance connected between said two second capacitors and configured to attain impedance matching to one of the first one and the last one of said plurality of phase shifters.

10. The bit phase shifter according to claim 9 , wherein each of said plurality of phase shifters comprises a single pole double throw (SPDT) switch switches, and

said SPDT switch is of a resonance type or a series shunt type.

11. The bit phase shifter according to claim 10 , wherein each said SPDT switch comprises a FET (Field effect transistor) connected to a respective one of said connection paths, and

each said FET is controlled by applying a voltage equal to or higher than 0 volt to a corresponding gate of each said FET.

12. The bit phase shifter according to claim 9 , wherein each said second inductance is about double each said first inductance.