RF MEMS switches and switch circuits
TL;DR: In this paper, the authors concentrate on electrostatic switches at 0.1-100 GHz with high reliability (100 million to 10 billion cycles) and wafer-scale manufacturing techniques.
Abstract: MEMS switches are devices that use mechanical movement to achieve a short circuit or an open circuit in the RF transmission line. RF MEMS switches are the specific micromechanical switches that are designed to operate at RF-to-millimeter-wave frequencies (0.1 to 100 GHz). The forces required for the mechanical movement can be obtained using electrostatic, magnetostatic, piezoelectric, or thermal designs. To date, only electrostatic-type switches have been demonstrated at 0.1-100 GHz with high reliability (100 million to 10 billion cycles) and wafer-scale manufacturing techniques. It is for this reason that this article will concentrate on electrostatic switches.
Citations
More filters
05 Apr 2012
TL;DR: Several examples of reconfigurable antennas for both terrestrial and space applications are highlighted, such as cognitive radio, multiple-input-multiple-output (MIMO) systems, and satellite communication.
Abstract: Reconfigurable antennas, with the ability to radiate more than one pattern at different frequencies and polarizations, are necessary in modern telecommunication systems. The requirements for increased functionality (e.g., direction finding, beam steering, radar, control, and command) within a confined volume place a greater burden on today's transmitting and receiving systems. Reconfigurable antennas are a solution to this problem. This paper discusses the different reconfigurable components that can be used in an antenna to modify its structure and function. These reconfiguration techniques are either based on the integration of radio-frequency microelectromechanical systems (RF-MEMS), PIN diodes, varactors, photoconductive elements, or on the physical alteration of the antenna radiating structure, or on the use of smart materials such as ferrites and liquid crystals. Various activation mechanisms that can be used in each different reconfigurable implementation to achieve optimum performance are presented and discussed. Several examples of reconfigurable antennas for both terrestrial and space applications are highlighted, such as cognitive radio, multiple-input-multiple-output (MIMO) systems, and satellite communication.
595Â citations
Patent•
02 Mar 2004TL;DR: An antenna having at least one main element and a plurality of parasitic elements is considered to have a coupling element or devices associated with them, the coupling elements or devices being tunable to control the degree of coupling between adjacent elements.
Abstract: An antenna having at least one main element and a plurality of parasitic elements. At least some of the elements have coupling elements or devices associated with them, the coupling elements or devices being tunable to thereby control the degree of coupling between adjacent elements. Controlling the degree of coupling allows a lobe associated with the antenna to be steered.
331Â citations
[...]
TL;DR: RF MEMS technology was initially developed as a replacement for GaAs HEMT switches and p-i-n diodes for low-loss switching networks and X-band to mm-wave phase shifters, but it has been found that its very low loss properties, its simple microwave circuit model and zero power consumption, and its high power handling capabilities make it the ideal tuning device for reconfigurable filters, antennas and impedance matching networks.
Abstract: RF MEMS technology was initially developed as a replacement for GaAs HEMT switches and p-i-n diodes for low-loss switching networks and X-band to mm-wave phase shifters. However, we have found that its very low loss properties (high device Q), its simple microwave circuit model and zero power consumption, its high power (voltage/current) handling capabilities, and its very low distortion properties, all make it the ideal tuning device for reconfigurable filters, antennas and impedance matching networks. In fact, reconfigurable networks are currently being funded at the same level-if not higher-than RF MEMS phase shifters, and in our opinion, are much more challenging for high-Q designs.
319Â citations
Cites background from "RF MEMS switches and switch circuit..."
...RF MEMS devices are well covered in [1] and [2] and consist of four different designs (Figure 1): Metal-contact switches 1) with excellent performance from dc to 100 GHz (see Radant MEMS [3])....
[...]
...A revisit of [1] and [2] leads to several known strengths for RF MEMS: Extremely low loss 1) 1, 0....
[...]
TL;DR: An overview of MEMS failure mechanisms that are commonly encountered is provided, focusing on the reliability issues of micro-scale devices, but, for some issues, the field of their macroscopic counterparts is also briefly touched.
300Â citations
TL;DR: In this paper, the authors review the recent progress in tunable and reconfigurable metasurfaces and metadevices through different active materials deployed together with the different control mechanisms including electrical, thermal, optical, mechanical, and magnetic, and provide the perspective for their future development for applications.
Abstract: Metasurfaces, two-dimensional equivalents of metamaterials, are engineered surfaces consisting of deep subwavelength features that have full control of the electromagnetic waves. Metasurfaces are not only being applied to the current devices throughout the electromagnetic spectrum from microwave to optics but also inspiring many new thrilling applications such as programmable on-demand optics and photonics in future. In order to overcome the limits imposed by passive metasurfaces, extensive researches have been put on utilizing different materials and mechanisms to design active metasurfaces. In this paper, we review the recent progress in tunable and reconfigurable metasurfaces and metadevices through the different active materials deployed together with the different control mechanisms including electrical, thermal, optical, mechanical, and magnetic, and provide the perspective for their future development for applications.
286Â citations
References
More filters
TL;DR: In this paper, the construction and performance of metal membrane radio frequency MEMS switches at microwave and millimeter-wave frequencies was described. But the authors focused on the performance of the switches in terms of on-off capacitance ratio.
Abstract: 'This letter details the construction and performance of metal membrane radio frequency MEMS switches at microwave and millimeter-wave frequencies. These shunt switches possess a movable metal membrane which pulls down onto a metal/dielectric sandwich to form a capacitive switch. These switches exhibit low loss (<0.25 dB at 35 GHz) with good isolation (35 dB at 35 GHz). These devices possess on-off capacitance ratios in the range of 80-110 with a cutoff frequency (figure of merit) in excess of 9000 GHz, significantly better than that achievable with electronic switching devices.
474Â citations
TL;DR: In this paper, a coplanar waveguide (CPW) transmission line with fixed-fixed beam MEMS bridge capacitors placed periodically over the transmission line, thus creating a slow-wave structure was designed.
Abstract: Wide-band switches and true-time delay (TTD) phase shifters have been developed using distributed microelectromechanical system (MEMS) transmission lines for applications in phased-array and communication systems. The design consists of a coplanar waveguide (CPW) transmission line (W=G=100 /spl mu/m) fabricated on a 500 /spl mu/m quartz substrate with fixed-fixed beam MEMS bridge capacitors placed periodically over the transmission line, thus creating a slow-wave structure. A single analog control voltage applied to the center conductor of the CPW line can vary the phase velocity of the loaded line by pulling down on the MEMS bridges to increase the distributed capacitive loading. The resulting change in the phase velocity yields a TTD phase shift. Alternatively, the control voltage can be increased beyond the pull-down voltage of the MEMS bridges such that the capacitive loading greatly increases and shorts the line to ground. The measured results demonstrate 0-60 GHz TTD phase shifters with 2 dB loss/118/spl deg/ phase shift at 60 GHz (/spl sim/4.5-ps TTD) and 1.8 dB loss/84/spl deg/ phase shift at 40 GHz. Also, switches have been demonstrated with an isolation of better than 40 dB from 21 to 40 and 40 to 60 GHz. In addition, a transmission-line model has been developed, which results in very close agreement with the measured data for both the phase shifters and switches. The pull-down voltage is 10-23 V, depending on the residual stress in the MEMS bridge. To our knowledge, this paper presents the first wide-band TTD MEMS phase shifters and wide-band switches to date.
440Â citations
20 May 2001
TL;DR: In this paper, the first experimental characterization of dielectric charging within capacitive RF MEMS switches has been demonstrated and their lifetimes were measured using a dual-pulse waveform with 30 to 65 V of actuation voltage.
Abstract: The first experimental characterization of dielectric charging within capacitive RF MEMS switches has been demonstrated. Standard devices have been inserted into a time domain setup and their lifetimes have been characterized as a function of actuation voltage. Switch lifetimes were measured using a dual-pulse waveform with 30 to 65 V of actuation voltage. Resulting lifetimes were between 10/sup 4/ and 10/sup 8/ switch actuations, demonstrating an exponential relationship between lifetime and actuation voltage.
359Â citations
TL;DR: In this article, the LC series resonance of the shunt switch was used to tune two and four-bridge "cross" switches from 10 to 40 GHz with an insertion loss of less than 0.3-0.6 dB, a return loss below -20 dB from 22 to 38 GHz in the up state, and a downstate isolation of 45-50 dB with only 1.5 pF of downstate capacitance.
Abstract: For pt.1 see ibid., vol.48, no.6, p.1045-1052 (2000). In this paper, the second of two parts, the equivalent RLC model of the shunt switch is used in the design of tuned two- and four-bridge "cross" switches from 10 to 40 GHz. The cross switch attained an insertion loss of less than 0.3-0.6 dB, a return loss below -20 dB from 22 to 38 GHz in the up state, and a down-state isolation of 45-50 dB with only 1.5 pF of down-state capacitance (C/sub d/). Also, an X-band microelectromechanical system (MEMS) switch with an insertion loss of less than 0.2 dB and an isolation of 35 dB is presented. This is done by inductively tuning the LC series resonance of the shunt switch. The MEMS bridge height is 1.5-2.5 /spl mu/m, resulting in a pull-down voltage of 15-25 V. Application areas are in low-loss high-isolation communication and radar.
320Â citations
26 Oct 1998
TL;DR: In this article, the authors present a tribological study of gold metallic contacts regarding contact resistance, heat dissipation, and surface damage in the normal-force regime of tens to hundreds of /spl mu/N, which is typical of the contact forces from microactuation.
Abstract: This work presents a tribological study of gold metallic contacts regarding contact resistance, heat dissipation, and surface damage in the normal-force regime of tens to hundreds of /spl mu/N, which is typical of the contact forces from microactuation. The purpose of this work is to present the micromechanical switch designer with practical information on gold contact phenomena in this force regime, as most work in micrometallic contacts has focused on contact forces greater than 1 mN. Results indicate actuation forces of several hundred /spl mu/N are required for reliable fully-metallic contacts, with resistance and current carrying ability primarily dependent on morphology, thermal management, and nm-depth material properties of the contact electrodes.
294Â citations