Design of millimeter-wave MEMS-based reconfigurable front-end circuits using the standard CMOS technology

Abstract

This paper describes the designs of three reconfigurable CMOS-MEMS front-end components for V-/W-band applications. The suspended MEMS structure is released through post-CMOS micromachining. To achieve circuit reconfigurability, dual-state and multi-state fishbone-beam-drive actuators are proposed herein. The reconfigurable bandstop is fabricated in a 0.35 µm CMOS process with the chip size of 0.765 × 0.98 mm2, showing that the stop-band frequency can be switched from 60 to 50 GHz with 40 V actuation voltage. The measured isolation is better than 38 dB at 60 GHz and 34 dB at 50 GHz, respectively. The bandpass filter-integrated single-pole single-throw switch, using the 0.18 µm CMOS process, demonstrates that insertion loss and return loss are better than 6.2 and 15 dB from 88 to 100 GHz in the on-state, and isolation is better than 21 dB in the off-state with an actuation voltage of 51 V. The chip size is 0.7 × 1.04 mm2. The third component is a reconfigurable slot antenna fabricated in a 0.18 µm CMOS process with the chip size of 1.2 × 1.2 mm2. By utilizing the multi-state actuators, the frequencies of this antenna can be switched to 43, 47, 50.5, 54, 57.5 GHz with return loss better than 20 dB. Those circuits demonstrate good RF performance and are relatively compact by employing several size miniaturizing techniques, thereby enabling a great potential for the future single-chip transceiver.

Design of multi-state actuator for mm-wave reconfigurable front-end circuits using CMOS-MEMS technologies

“…However, when both sets are rotor fingers, more actuation states can be achieved. If same displacement are chosen for d 1 and d 2 , the finger gap g 2 from state(b) will be the same as g 6 in state(f), while g 3 from state(c) will be also identical to g 7 in state(g), leading to five-state motions.…”

“…In our previous work [6][7][8], four different reconfigurable front-end circuits using CMOS-MEMS technology been successfully designed and demonstrated in V-/W-band, revealing that CMOS-MEMS could be a promising solution for mm-wave applications. Within [6][7][8], the electrostatic laminated actuator driven by parallel beams has been proposed to change the interdigitated capacitance values, leading to the circuit reconfigurability. However, the tuning capability shown in [6][7] is still limited.…”

“…Within [6][7][8], the electrostatic laminated actuator driven by parallel beams has been proposed to change the interdigitated capacitance values, leading to the circuit reconfigurability. However, the tuning capability shown in [6][7] is still limited.…”

Frequency-tunable CMOS-MEMS slot antenna

“…Also, those literatures are primarily focused on frequencies below 30 GHz. In our recent work [4], three reconfigurable CMOS-MEMS front-end circuits, including a bandstop filter, a filter-integrated switch, and a slot antenna, have been successfully demonstrated for V-/W-band operation. This paper is the extension from the slot antenna design with the pattern measurement data being provided, which further validates the feasibility of the proposed structure.…”