A phase shift module is a microwave network module which provides a controllable phase shift of the RF signal.Microwave Solid State Circuit Design, 2nd Ed., by Inder Bahl and Prakash Bhartia, John Wiley & Sons, 2003 (Chapter 12)RF MEMS Theory, Design and Technology by Gabriel Rebeiz, John Wiley & Sons, 2003 (Chapter 9-10)Antenna Engineering Handbook, 4th Ed., by John Volakis, McGraw-Hill, 2007 (Chapter 21) Phase shifters are used in phased arrays.Phased Array Antennas, 2nd Ed., by R. C. Hansen, John Wiley & Sons, 1998Phased Array Antenna Handbook, 2nd Ed., by Robert Mailloux, Artech House, 2005Phased Array Antennas by Arun K. Bhattacharyya, John Wiley & Sons, 2006
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.Microwave Phase Shifter information from Herley General Microwave 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 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) [ps2/nm] Gain [dB] if active, loss [dB] if passive Linearity: IP3, P1dB [dBm] Phase shift / noise figure [°/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
External links "Phase Shifters", Microwaves101.com Microwave Phase Shifter information from Herley General Microwave A low cost electro-mechanical phase shifter design, including a brief summary of solid state methods @ www.activefrance.com