Xinglong Guo

A novel tunable low-pass filter based on MEMS and CPW

This paper presents a new type of tunable low-pass filter for millimeter-waves. The filter is based on the slow-wave coplanar waveguide (CPW) lines and tuned by the MEMS capacitive shunt switches. There are 5 switches which can provide two orders of tunable mode. In the first order tuning, the 3dB cut-off frequency changes from 8.2GHz to 10.5GHz, and the second order tuning is 8.2GHz to 16.8GHz. The tested results show that the pass-band ripple is less than 2dB and the maximal out-of-band rejection is better than 20dB. The driven voltages of the switches are around 40V.

Miniature and tunable filters with MEMS switches

In this paper, fully monolithic tunable millimeter-wave filters with tapped-line feedings are proposed using the CPW-based periodic structures with novel multiple-contact MEMS switches. Millimeter-wave low-pass were designed, fabricated, and tested. The cascaded CPW-based periodic structures, with low-pass intrinsic filtering characteristics, are reconfigured into a self-similar single unit cell by the operation of the novel multiple-contact MEMS switches with single actuation. The measured results of the reconfigurable low-pass filter show the 3-dB cutoff frequency change from 19 to 11 GHz with very small change in the average insertion loss from 1.3 to 1.9 dB. The chip size of the low-pass is 4.0 mm times 1.6 mm.

Design and Fabrication of Miniature Antenna Based on Silicon Substrate for Wireless Communications

In this paper, a novel compact CPW-fed slot small antenna was designed and fabricated on high-resistivity silicon (HR-Si) by micro-electronics process. The results of simulation are consistent with results of measurement for the antenna. The mode of the antenna is vertical and horizontal bidirectional radiations. The gain of antenna is 2.5 dB, and the resonance frequency approximately is 3 GHz. This fabrication can be compatible with antenna integration and CMOS process. The parameters of this antenna are for reference radar antenna system of Unmanned Aerial Vehicles (UAV), satellite transmission, and communication.

A Novel Method of Removing Polyimide Sacrificial Layer

Due to the trade secrets and intellectual property, there are still many aspects of MEMS switches which are not understand well and are currently under investigation. In this paper, our report shows that MEMS can be released using O2 and a little carbon powder at the same time. The relationship between the removing polyimide time and the cure temperature is presented using carbon powder in the quartz vacuum cavity when etching polyimide sacrificial layer. It greatly reduces removing polyimide sacrificial layer time. It is highly important for MEMS fabrication process technology. The process is capable of various applications in surface micromachining process, and can be applied in fabricating RF MEMS switches, tunable capacitors, high-Q suspended inductors and suspended-gate MOSFETs

A reconfigurable RF MEMS low-pass filter, based on CPW periodic structures

This paper addresses the design and the realization of millimeter wave tunable filters using multiple-contact MEMS switches. The two unit cell filter based on slow-wave coplanar waveguide(CPW) periodic structure are reconfigured into a self-similar single unit cell by the operation of MEMS switches with single actuation. The 3-dB cutoff frequency of the low-pass filter was shifted from 12.5 GHz to 6.1 GHz, which exhibits excellent performance on small size, low insertion loss and is compatible with monolithic microwave integrated circuit technologies. The tested results show that the pass-band ripple is less than 0.5 dB and the out-of-band rejection is better than 40 dB. The driven voltages of the switches are around 25 V.

Design and modeling of reconfigurable MEMS low pass filter

This paper presents the design and modeling of a unit cell for reconfigurable microwave microelectromechanical systems (MEMS) low pass filters (LPF), with reconfigurable inductance and capacitance. Lumped elements are introduced here to approximate the characteristics of the distributed filters, and then optimization is performed to obtain the superior characteristics as needed. LPFs with arbitrary cut-off frequency between 10GHz to 30GHz can be optimized corresponding to this model. Using this prototype, the reconfigurable LPF has a cut-off frequency switching from 7.8GHz to 15.3GHz, with ripple below 2dB and out-of-band rejection better than 40dB in both states, which demonstrates the validation of the proposed model

Tunable band-pass filters using Mems switches

In this paper, fully monolithic tunable millimeter-wave filters with taped-line feedings are proposed using the CPW-based periodic structures with novel multiple-contact MEMS switches. Millimeter-wave band-pass were designed, fabricated, and tested. The cascaded CPW-based periodic structures, with band-pass intrinsic filtering characteristics, are reconfigured into a self-similar single unit cell by the operation of the novel multiple-contact MEMS switches with single actuation. The measured results of the reconfigurable band-pass filter at 11.2 to 29.1 GHz. The chip size of the band-pass filter is 3 mm × 2 mm.

Fitting SOC miniature MEMS reconfigurable antenna

The paper demonstrates miniature reconfigurable antenna designed and fabricated on the high resistivity Si substrate. This antenna can integrate with a microelectromechanical system (MEMS) actuator for reconfiguring the operating frequency and is used for SOC (system on the chip). The switching between the two different frequency bands is achieved through the use of RF-MEMS switches. According to the ideal open/closed experiment results, when switch is on and off, the antenna operating frequency is 27.7GHz and 39.5GHz with low return loss, respectively. It is important for the next generation wireless communications and integrated antenna system on the chip