A Ku band 5 bit MEMS phase shifter for active electronically steerable phased array applications

Abstract

The design, fabrication and measurement of a 5 bit Ku band MEMS phase shifter in different configurations, i.e. a coplanar waveguide and microstrip, are presented in this work. The development architecture is based on the hybrid approach of switched and loaded line topologies. All the switches are monolithically manufactured on a 200 µm high resistivity silicon substrate using 4 inch diameter wafers. The first three bits (180°, 90° and 45°) are realized using switched microstrip lines and series ohmic MEMS switches whereas the fourth and fifth bits (22.5° and 11.25°) consist of microstrip line sections loaded by shunt ohmic MEMS devices. Individual bits are fabricated and evaluated for performance and the monolithic device is a 5 bit Ku band (16–18 GHz) phase shifter with very low average insertion loss of the order of 3.3 dB and a return loss better than 15 dB over the 32 states with a chip area of 44 mm2. A total phase shift of 348.75° with phase accuracy within 3° is achieved over all of the states. The performance of individual bits has been optimized in order to achieve an integrated performance so that they can be implemented into active electronically steerable antennas for phased array applications.

Design Guideline for a Cantilever-Type MEMS Switch with High Contact Force

“…Electrostatic MEMS switches are fabricated by microelectronic techniques and can be easily integrated with CMOS circuits [13,14]. Combining multiple switches on a single chip allows the fabrication of reconfigurable devices such as phase shifters [15][16][17], filters [18,19], attenuators [20][21][22], and amplifiers [23,24].…”

“…A miniature cantilever ensures stress robustness and short switching time [46]. However, the cantilever-based devices typically demonstrate low contact force of several tens of micronewtons [15,16,[46][47][48]. This paper describes a comprehensive strategy for increasing the contact force of the conventional MEMS switch without enlargement of its lateral size.…”

Design and numerical demonstration of a 2D millimeter-wave beam-scanning reflectarray based on liquid crystals and a static driving technique

“…For reconfigurable arrays, electronically tunable devices, such as phase shifters, resonators, and antennas, have been crucial in applications requiring beam forming and beam scanning [1][2][3]. Phase shifters, such as MEMS [4,5], PIN or varactor diode [6][7][8][9], ferroelectric [10][11][12] and liquid crystals (LCs) [13,14] have been used to construct the array elements. As the frequency increases to millimeter-wave band, MEMS or diode based arrays [15,16] are difficult to manufacture, and present high losses and parasitic effects because the package size and the wavelength are comparable, while ferroelectric films have significant losses above 40 GHz [17].…”

Photonics-Assisted Super-Octave Microwave Phase Shifter

“…Microwave phase shifter is one of the most essential components in phased array beamforming, phase coding, microwave filters, phase noise measurement, linear frequency modulated signals generation, and interference cancellation [1]- [5]. Conventional electrical phase shifters suffer from limited phase-shifting range [6]- [8], limited frequency-operating range [6], [8], limited phase-tuning resolution [6]- [9], and frequency-dependent phase shifts [7], [8]. In recent years, photonics-assisted microwave phase shifters have been reported based on different techniques such as stimulated Brillouin scattering [10], polarization maintaining fiber Bragg grating [11], highly nonlinear fiber [12], parallel modulators [13], polarization-dependent modulator [14], [15], and Fourier-domain optical processor (FD-OP) [16], [17].…”