Phase Shifter | Phraygun

Phase Shifters

Objective

Ensure the integrity of each of our four phase shifters.

Proof of Concept

Input an RF signal and measure the output RF signal of each phase shifter for various controlled bias voltage values, ranging from 1-15 volts. Graph the measured phase shift versus the bias voltage in order to match the given graph on the datasheet. The phase of the output signal will be measured with a mini-Vector Network Analyzer (VNA), or a Keysight FieldFox.

Pass criteria: Phase shift accuracy <= 10º
Fail criteria: Phase shift accuracy > 10º

Methods

Need to make sure that the phase shifter can perform a phase shift from 0 degrees to 180 degrees in the 915MHz ISM frequency band. We performed this test by supplying the phase shifter with a control voltage ranging from 0V to 15V in steps of 0.5V. Due to the phase shifters being surface mounted and because it is an RF component, we designed a PCB in Eagle to be manufactured and soldered the necessary components onto the PCB. The PCB is designed for the phase shifter, amplifier and SMA connectors, but in this test we only soldered the phase shifters to the PCB. We specifically picked the following frequencies: 917MHz, 920MHz, 925MHz, and 928MHz. Additionally we chose these frequencies to observe which frequency resulted in the largest phase shift range. Once all the phase shifters were tested, we set our reference phase shifter at the frequency with the largest resultant phase shifter range.

Results

Our ideal phase shift would be from 0º to 180º for all of the individual phase shifters. If the phase shift is larger than 180º that is good too because that means we are able to scan a larger area. We scanned at different frequencies to see how the phase shift would change at those different frequencies. After observing our results, we found out that the different frequencies did not have that much of a phase shift difference. These results match the datasheet of the JSPHS-1000+ Phase Shifter.

PCB 1