Samiksha Jaiswal (Editor)

Phase shift module

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Phase shift module

A phase shift module is a microwave network module which provides a controllable phase shift of the RF signal. Phase shifters are used in phased arrays.

Contents

Classification

  • Active versus passive: Active phase shifters provide gain, while passive phase shifters are lossy.
  • Active:
  • Applications: active electronically scanned array (AESA), passive electronically scanned array (PESA)
  • Gain: The phase shifter amplifies while phase shifting
  • Noise figure (NF)
  • Reciprocity: not reciprocal
  • Passive:
  • Applications: active electronically scanned array (AESA), passive electronically scanned array (PESA)
  • Loss: the phase shifter attenuates while phase shifting
  • NF: NF = loss
  • Reciprocity: reciprocal
  • Analog versus digital:
  • Analog phase shifters provide a continuously variable phase shift or time delay.
  • Digital phase shifters provide a discrete set of phase shifts or time delays. Discretization leads to quantization errors. Digital phase shifters require parallel bus control.
  • Differential, single-ended or waveguide:
  • Differential transmission line: A differential transmission line is a balanced two-conductor transmission line in which the phase difference between currents is 180 degrees. The differential mode is less susceptible to common mode noise and cross talk.
  • Antenna selection: dipole, tapered slot antenna (TSA)
  • Examples: coplanar strip, slotline
  • Single-ended transmission line: A single-ended transmission line is a two-conductor transmission line in which one conductor is referenced to a common ground, the second conductor. The single-ended mode is more susceptible to common-mode noise and cross talk.
  • Antenna selection: double folded slot (DFS), microstrip, monopole
  • Examples: CPW, microstrip, stripline
  • Waveguide
  • Antenna selection: waveguide, horn
  • Frequency band
  • One-conductor or dielectric transmission line versus two-conductor transmission line
  • One-conductor or dielectric transmission line (optical fibre, finline, waveguide):
  • Modal
  • No TEM or quasi-TEM mode, not TTD or quasi-TTD
  • Higher-order TE, TM, HE or HM modes are distorted
  • Two-conductor transmission line (CPW, microstrip, slotline, stripline):
  • Differential or single-ended
  • TEM or quasi-TEM mode is TTD or quasi-TTD
  • Phase shifters versus TTD phase shifter
  • A phase shifter provides an invariable phase shift with frequency, and is used for fixed-beam frequency-invariant pattern synthesis.
  • A TTD phase shifter provides an invariable time delay with frequency, and is used for squint-free and ultra wideband (UWB) beam steering.
  • Reciprocal versus non-reciprocal
  • Reciprocal: T/R
  • Non-reciprocal: T or R
  • Technology
  • Non semi-conducting (ferrite, ferro-electric, RF MEMS, liquid crystal):
  • Passive
  • Semi-conducting (RF CMOS, GaAs. SiGe, InP, GaN or Sb):
  • Active: BJT or FET transistor based MMICs, RFICs or optical ICs
  • Passive: PIN diode based hybrids
  • Design
  • Loaded-line:
  • Distortion:
  • Distorted if lumped
  • Undistorted and TTD if distributed
  • Reflect-type:
  • Applications: reflect arrays (S11 phase shifters)
  • Distortion:
  • Distorted if S21 phase shifter, because of 3 dB coupler
  • Undistorted and TTD if S11 phase shifter
  • Switched-network
  • Network:
  • High-pass or low-pass
  • π or T
  • Distortion:
  • Undistorted if the left-handed high-pass sections cancel out the distortion of the right-handed low-pass sections
  • Switched-line
  • Applications: UWB beam steering
  • Distortion: undistorted and TTD
  • Vector summing

    • Figures of Merit

  • Number of Effective bits, if digital [Bit]
  • Biasing: current-driven, high-voltage electrostatic [mA,V]
  • DC power consumption [mW]
  • Distortion: group velocity dispersion (GVD) [ps/(km.nm)]
  • Gain [dB] if active, loss if [dB] if passive
  • Linearity: IP3, P1dB [dBm]
  • Phase shift / noise figure [deg/dB] (phase shifter) or time delay / noise figure [ps/dB] (TTD phase shifter)
  • Power handling [mW, dBm]
  • Reliability [Cycles, MTBF]
  • Size [mm2]
  • Switching time [ns]

    • References

    Phase shift module Wikipedia
    (Text) CC BY-SA


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