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Two types of 3-bit phase shifters
for phased array antennas are developed. One is
a switched line type with PIN diodes and the other
is a reflection type with GaAs FET 's.
The PIN diode phase shifter is developed
to achieve a low loss by optimum design of the RF
and bias circuits. As a result, the insertion loss
is 1.3dB maximum and the phase error is less than
15 degrees. These characteristics are good enough
to make high gain phased array antennas.
The FET phase shifter has advantages, such as simple
bias circuit and low power consumption because the
FET is switched by only the DC voltage at a gate
isolated from the RF line. So we have developed
a low loss switching FET, and designed a reflection
type phase shifter which consists of a interdigitated
coupler and the phase shift circuit with the developed
FET. As a result, the insertion loss is 1.9dB maximum
and the size is 50mm´60mm . The phase shifter has
simple configuration suitable for simple and thin
phased array antennas.
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