Advantages of RF Phase Shifter | Disadvantages of RF Phase Shifter
This page covers advantages and disadvantages of RF Phase Shifter. It mentions benefits or advantages of RF Phase Shifter and drawbacks or disadvantages of RF Phase Shifter.
What is RF Phase Shifter ?
Introduction:
The RF phase shifter as the name suggests shifts the phase angle of the RF signal provided
at its input. It does not change the amplitude of the RF signal. There are different types of
RF phase shifters as per various requirements viz. analog phase shifter, digital phase shifter
and mechanical phase shifter.
Following figure shows major application of RF phase shifters used in phased array antenna system.
In this system, phase of signal transmitted from multiple antennas are shifted by different angles
to form beam according to the requirement. This antenna array system is also called as MIMO.
This system is used in 4G/5G base station, 4G/5G smartphone etc.
Following mathematical equation can be used to simulate phase shift and other parameters.
X(t) = A * cos(2*π*f_c*t + θ)
Where,
X(t) is baseband input signal
A is amplitude of baseband signal
f_c is RF carrier frequency
t is the time samples
θ is phase shift introduced by RF phase shifter device.
Following are the specifications of RF Phase Shifter considered for selection.
• Control interface such as analog, digital or mechanical
• Phase angle (degrees)
• Insertion loss (dB)
• Frequency range of operation
• Switching speed
• Power (Input/Output)
• VSWR or return loss
• Linearity (Degree to which phase shift is linear with respect to voltage/current)
• Supply voltage
• Package type, connector types, size, cost etc.
Benefits or advantages of RF Phase Shifter
Following are the benefits or advantages of RF Phase Shifter:
➨It allows precise control of RF signal propagation by changing phase of the RF signal.
➨It controls direction of beam transmitted by antenna and hence improves signal strength in
specific direction and reduces interference from other systems.
➨RF phase shifters are used in MIMO antenna array system to create multiple paths or multiple beams which
helps to improve system capacity and consecutively data rate.
➨It creates multiple signal paths which improves immunity of the system against jamming.
➨They are used in antenna diversity systems to improve signal quality and reduce fading.
➨RF phase shifters can be controlled from remote end which is very useful where physical tuning of
the phase is not feasible.
➨It offers low insertion loss and hence signal amplitude is not affected.
Drawbacks or disadvantages of RF Phase Shifter
Following are the limitations or drawbacks or disadvantages of RF Phase Shifter.
➨They are designed to operate over narrow frequency band.
➨RF phase shifters support limited phase shift range.
➨They have limited linearity and hence affect accuracy of the phase shift.
➨They are required to be calibrated for accurate phase shifting.
➨They are sensitive to temperature changes which affect performance.