Patent Publication Number: US-2023140449-A1

Title: Two-stage actuation in mems ohmic relays

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 63/275,571 and the benefit of U.S. Provisional Patent Application Ser. No. 63/275,851, both filed on Nov. 4, 2021, the disclosures of which are hereby incorporated herein by reference in their entireties. 
    
    
     FIELD OF THE DISCLOSURE 
     Embodiments of the disclosure generally relate to micro-electro-mechanical system (MEMS) switches or MEMS relays for use in electrical circuits. More particularly, embodiments of the disclosure relate to MEMS switches or MEMS relays that actuate or switch to an on state in two stages. 
     BACKGROUND 
     MEMS switches and MEMS relays (hereinafter “MEMS switch” or “MEMS switches”) are used in many types of applications, from wireless communications to consumer products. For example, MEMS switches are currently one of the best available options for an implementation of very high-performance switches that operate from direct current (DC) up to radio frequency (RF) and millimeter wave spectrum ranges. For this technology to be successfully adopted in state-of-the-art transmitting and/or receiving radio frequency devices, the reliability of the MEMS switch in terms of mean time to failure and ruggedness is evaluated against application-level requirements. While the performance benefits of MEMS technology are widely recognized both in the industry and in the academic world, its real or perceived shortcomings in terms of reliability have been a long-standing issue that has delayed wide scale adoption of MEMS technology. 
     One aspect related to the reliability of MEMS technology is the effect of switching (either opening or closing the switch) while DC or RF power is applied, a use condition often referred to as “hot switching.” To date, hot switching has been addressed in two ways. One approach is a system-level specification to avoid presenting the MEMS switch with significant power during switching events. This safe-operating-conditions approach is unfortunately not always an option, and there are applications where it is impossible or extremely cumbersome to implement. 
     A second approach is the combination of the MEMS switch with a secondary protection switch, implemented in a different technology that is more rugged from a hot switching perspective. One problem with the second approach is that it typically degrades the key RF performance benefits offered by the MEMS device, making the MEMS switch and the secondary protection switch less appealing compared with traditionally non-MEMS implementations. 
     SUMMARY 
     Embodiments disclosed herein provide techniques for limiting a power level (e.g., a voltage level) presented to a microelectromechanical system (MEMS) switch during the opening transition event and the closing transition event. The techniques can enable a significant extension in the reliability of the MEMS switches in terms of the number of operating life cycles and/or maximum power handling. By appropriate fabrication process and device design, this protection is implemented within the same intrinsic MEMS switch, in the form of a two-stage transition: a first stage addresses voltage suppression across a dedicated conduction path with current limiting resistance; and a second stage enables the main conduction path for signal transmission. This two-stage operation does not require extra circuitry or special provisions in the application. 
     In an aspect, a microelectromechanical system (MEMS) switch includes a first conductive contact, a second conductive contact, a third conductive contact, and a fourth conductive contact disposed over a substrate. The first conductive contact and the second conductive contact form a first set of conductive contacts, and the third conductive contact and the fourth conductive contact form a second set of conductive contacts. The first set of conductive contacts are positioned between the third conductive contact and the fourth conductive contact in the second set of conductive contacts. A movable beam is suspended over the first set of conductive contacts and the second set of conductive contacts. The first set of conductive contacts and the movable beam are operable to create a first conduction path when the movable beam contacts the first set of conductive contacts in a first stage of actuation of the MEMS switch. The second set of conductive contacts and the movable beam are operable to create a second conduction path when the movable beam contacts the second set of conductive contacts in a second stage of actuation of the MEMS switch. 
     In another aspect, a MEMS cell includes multiple MEMS switches operably connected in parallel, and a first conductor and a second conductor positioned in parallel below the multiple MEMS switches. Each switch includes a first conductive contact, a second conductive contact, a third conductive contact, and a fourth conductive contact disposed over a substrate. The first conductive contact and the second conductive contact form a first set of conductive contacts, and the third conductive contact and the fourth conductive contact form a second set of conductive contacts. The first set of conductive contacts are positioned between the third conductive contact and the fourth conductive contact in the second set of conductive contacts. A movable beam is suspended over the first set of conductive contacts and the second set of conductive contacts. The first conductive contact and the third conductive contact in a first set of MEMS switches are operably connected to the first conductor. The second conductive contact and the fourth conductive contact in a second set of MEMS switches are operably connected to the second conductor. The first set of MEMS switches includes one or more MEMS switches. The second set of MEMS switches includes one or more different MEMS switches. 
     In yet another aspect, a method of operating a MEMS switch includes initiating actuation of the MEMS switch and establishing a first conduction path between a first set of conductive contacts and a movable beam when the movable beam contacts the first set of conductive contacts during a first stage of actuation of the MEMs switch. A second conduction path is established between a second set of conductive contacts and the movable beam when the movable beam contacts the second set of conductive contacts during a second stage of actuation of the MEMs switch. 
     In another aspect, any of the foregoing aspects individually or together, and/or various separate aspects and features as described herein, may be combined for additional advantage. Any of the various features and elements as disclosed herein may be combined with one or more other disclosed features and elements unless indicated to the contrary herein. 
     Those skilled in the art will appreciate the scope of the present disclosure and realize additional aspects thereof after reading the following detailed description of the preferred embodiments in association with the accompanying drawing figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       The accompanying drawing figures incorporated in and forming a part of this specification illustrate several aspects of the disclosure, and together with the description serve to explain the principles of the disclosure. 
         FIG.  1 A  illustrates a vertical cross-sectional view of a first MEMS switch in an open or off state; 
         FIG.  1 B  illustrates the first MEMS switch shown in  FIG.  1 A  activated and deformed to a point where the movable beam contacts a set of stoppers; 
         FIG.  1 C  illustrates the first MEMS switch shown in  FIG.  1 B  activated and further deformed to a point where the movable beam contacts the set of stoppers and a set of conductive contacts; 
         FIG.  2 A  illustrates a vertical cross-sectional view of a second MEMS switch in an open or off state in accordance with embodiments of the disclosure; 
         FIG.  2 B  illustrates the second MEMS switch shown in  FIG.  2 A  activated and deformed to a point where the movable beam contacts a first set of conductive contacts in accordance with embodiments of the disclosure; 
         FIG.  2 C  illustrates the second MEMS switch shown in  FIG.  2 B  activated and deformed to a point where the movable beam contacts the first set of conductive contacts and a second set of conductive contacts in accordance with embodiments of the disclosure; 
         FIG.  3    illustrates a vertical cross-sectional view of a third MEMS switch in accordance with embodiments of the disclosure; 
         FIG.  4    illustrates a top view of a MEMS switch in accordance with embodiments of the disclosure; 
         FIG.  5    illustrates a top view of multiple MEMS switches mechanically and electrically connected together in accordance with embodiments of the disclosure; 
         FIG.  6    illustrates a top view of a first cell in accordance with embodiments of the disclosure; 
         FIG.  7    illustrates a top view of a second cell in accordance with embodiments of the disclosure; 
         FIG.  8 A  illustrates a vertical cross-sectional view of a portion of the MEMS switch taken along line  8 A- 8 A in  FIG.  7    in accordance with embodiments of the disclosure; 
         FIG.  8 B  illustrates a vertical cross-sectional view of a portion of the MEMS switch taken along line  8 B- 8 B in  FIG.  7    in accordance with embodiments of the disclosure; 
         FIG.  9    illustrates a top view of a third cell in accordance with embodiments of the disclosure; 
         FIG.  10    illustrates a top view of a fourth cell in accordance with embodiments of the disclosure; 
         FIG.  11 A  illustrates a vertical cross-sectional view of a portion of the MEMS switch taken along line  11 A- 11 A in  FIG.  10    in accordance with embodiments of the disclosure; 
         FIG.  11 B  illustrates a vertical cross-sectional view of a portion of the MEMS switch taken along line  11 B- 11 B in  FIG.  10    in accordance with embodiments of the disclosure; 
         FIG.  12    illustrates a top view of a fifth cell in accordance with embodiments of the disclosure; and 
         FIG.  13    illustrates a method of operating a MEMS switch in accordance with embodiments of the disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     The embodiments set forth below represent the necessary information to enable those skilled in the art to practice the embodiments and illustrate the best mode of practicing the embodiments. Upon reading the following description in light of the accompanying drawing figures, those skilled in the art will understand the concepts of the disclosure and will recognize applications of these concepts not particularly addressed herein. It should be understood that these concepts and applications fall within the scope of the disclosure and the accompanying claims. 
     It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and, similarly, a second element could be termed a first element, without departing from the scope of the present disclosure. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items. 
     It will be understood that when an element such as a layer, region, or substrate is referred to as being “on” or extending “onto” another element, it can be directly on or extend directly onto the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” or extending “directly onto” another element, there are no intervening elements present. Likewise, it will be understood that when an element such as a layer, region, or substrate is referred to as being “over” or extending “over” another element, it can be directly over or extend directly over the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly over” or extending “directly over” another element, there are no intervening elements present. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. 
     Relative terms such as “below” or “above” or “upper” or “lower” or “horizontal” or “vertical” may be used herein to describe a relationship of one element, layer, or region to another element, layer, or region as illustrated in the Figures. It will be understood that these terms and those discussed above are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises,” “comprising,” “includes,” and/or “including” when used herein specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
     Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure belongs. It will be further understood that terms used herein should be interpreted as having a meaning that is consistent with their meaning in the context of this specification and the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. 
     Embodiments are described herein with reference to schematic illustrations of embodiments of the disclosure. As such, the actual dimensions of the layers and elements can be different, and variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are expected. For example, a region illustrated or described as square or rectangular can have rounded or curved features, and regions shown as straight lines may have some irregularity. Thus, the regions illustrated in the figures are schematic and their shapes are not intended to illustrate the precise shape of a region of a device and are not intended to limit the scope of the disclosure. Additionally, sizes of structures or regions may be exaggerated relative to other structures or regions for illustrative purposes and, thus, are provided to illustrate the general structures of the present subject matter and may or may not be drawn to scale. Common elements between figures may be shown herein with common element numbers and may not be subsequently re-described. 
     The present disclosure relates to extending the reliability of a MEMS switch. The approaches according to the present disclosure are different from other known approaches which rely on external circuitry, mostly using hybrid technology, or added redundancy within the MEMS switch at the expense of performance. The improved reliability in the present disclosure has little to no impact on overall RF performance without the need of further provisions at the circuit level or system level in an application. 
     The underlying concept of the present disclosure is that a MEMS switch can be engineered in such a way that, during the actuation of the MEMS switch, the movable beam of the MEMS switch is brought into contact with multiple (sets of) conductive contacts, each set at a distinguished stage of the actuation of the MEMS switch. Contacting a first set of conductive contacts in a first stage of actuations limits the voltage level presented to the MEMS switch during opening and closing transition events. The first stage of actuation provides voltage suppression across a dedicated conduction path with a current limiting resistance. In a second stage of actuation, the movable beam contacts the first set of conductive contacts and a second set of conductive contacts. The second stage of actuation enables a second conduction path for signal transmission. 
       FIG.  1 A  illustrates a cross-sectional view of a first MEMS switch  100  in an open or turned off state. The cross-sectional view of the first MEMS switch  100  is taken along a plane where movement of a movable beam  102  occurs. The first MEMS switch  100  includes the movable beam  102  that spans across a cavity  104 . The movable beam  102  is made of one or more conductive materials or is made of a combination of conductive and dielectric materials. In non-limiting nonexclusive examples, the movable beam  102  is made of titanium, titanium nitride, titanium aluminum, titanium aluminum nitride, aluminum, tungsten, platinum, iridium, rhodium, ruthenium, ruthenium oxide, molybdenum, indium tin oxide, silicon-dioxide, or combinations thereof. 
     A first attachment element  106  is used to attach a first end  108  of the movable beam  102  to a first anchor  110 . A second attachment element  112  is used to attach a second end  114  of the movable beam  102  to a second anchor  116 . The second end  114  of the movable beam  102  is opposite the first end  108  of the movable beam  102 . In the illustrated embodiment, the first attachment element  106  and the second attachment element  112  are springs. In other embodiments, the first attachment element  106  and the second attachment element can be implemented differently. 
     A first stopper  118  and a second stopper  120  are disposed under the movable beam  102 . The first stopper  118  and the second stopper  120  may be made of any suitable material or materials, such as a conductive material that is covered by an insulating material. The first stopper  118  and the second stopper  120  form a set of stoppers  122 . Although  FIG.  1 A  shows two (2) stoppers, other embodiments can include one or more stoppers. 
     A first conductive contact  124  and a second conductive contact  126  are disposed under the movable beam  102 . The first conductive contact  124  and the second conductive contact  126  are made of a conductive material, such as titanium, titanium nitride, ruthenium, ruthenium oxide, titanium aluminum, titanium aluminum nitride, aluminum, tungsten, platinum, iridium, rhodium, molybdenum, indium tin oxide, or combinations thereof. The first conductive contact  124  and the second conductive contact  126  form a set of conductive contacts  128 . Although  FIG.  1 A  shows two conductive contacts, other embodiments can include one or more conductive contacts. 
     A signal source  130  is operably connected to the first conductive contact  124 . The signal source  130  represents circuitry that provides a signal, such as a radio-frequency (RF) signal, to the first MEMS switch  100 . A resistor  132  is operably connected between the signal source  130  and a reference voltage  134  (e.g., ground). A load  136  is operably connected between the second conductive contact  126  and the reference voltage  134 . 
     The movable beam  102  is suspended over the set of stoppers  122  and the set of conductive contacts  128 . In the illustrated embodiment, the set of stoppers  122  is positioned between the first conductive contact  124  and the second conductive contact  126 . The movable beam  102  is operable to bend or deform to contact the set of stoppers  122  and the set of conductive contacts  128 . As will be described in more detail in conjunction with  FIG.  1 B  and  FIG.  1 C , the first MEMS switch  100  transitions to a closed or an on state through a two-stage actuation process. 
       FIG.  1 B  illustrates the first MEMS switch  100  shown in  FIG.  1 A  activated and deformed to a point where the movable beam  102  contacts the set of stoppers  122 . To cause the movable beam  102  to bend downward, a power signal (e.g., a voltage signal) is applied to pull-down electrodes (not shown in  FIG.  1   ) that are positioned in a substrate below the set of stoppers  122  and the set of conductive contacts  128 . When the power signal is applied across the pull-down electrodes, the pull-down electrodes electrostatically pull the movable beam  102  downward.  FIG.  1 B  depicts a first stage of actuation where the movable beam  102  is deformed and contacts the set of stoppers  122 . If the set of stoppers  122  are covered by an insulating material, a conduction path is not created when the movable beam  102  contacts the set of stoppers  122 . If the set of stoppers  122  are made of a conductive material, the set of stoppers  122  are electrically floating so a conduction path is not formed when the movable beam  102  contacts the set of stoppers  122 . 
       FIG.  1 C  illustrates the first MEMS switch  100  shown in  FIG.  1 B  activated and further deformed to a point where the movable beam  102  contacts the set of stoppers  122  and the set of conductive contacts  128 . As the power signal continues to be applied across the pull-down electrodes, the pull-down electrodes electrostatically pull the movable beam  102  down further.  FIG.  1 C  depicts a second stage of actuation where the movable beam  102  is deformed and contacts the set of stoppers  122  and the set of conductive contacts  128 . Since the set of conductive contacts  128  are made of a conductive material, a conduction path is formed when the movable beam  102  contacts the set of conductive contacts  128 . The first MEMS switch  100  is closed or turned on when the movable beam  102  contacts the set of conductive contacts  128 , and a signal (e.g., an RF signal) is routed from the signal source  130  to the first conductive contact  124 , from the first conductive contact  124  to the movable beam  102 , across the movable beam  102  to the second conductive contact  126 , and from the second conductive contact  126  to the load  136 . A resistor symbol  138  represents an electrical resistance of the movable beam  102  as the signal propagates along the movable beam  102 . 
     One issue with the first MEMS switch  100  is that during the closure of the first MEMS switch  100  ( FIG.  1 C ), the first conductive contact  124  and the second conductive contact  126  are exposed to significant electric fields and electrical currents, which can potentially damage the first conductive contact  124  and the second conductive contact  126 . When the first conductive contact  124  and/or the second conductive contact  126  are damaged, the reliability of the first MEMS switch  100  can be negatively impacted. For example, the movable beam  102  and one or both first conductive contact  124  and second conductive contact  126  can stick together, resulting in a functional failure of the first MEMS switch  100  (e.g., reduced OFF state isolation). 
       FIG.  2 A  through  FIG.  13    disclose techniques that provide protection to a MEMS switch from electric fields and electrical currents during the closing or opening transients. In certain embodiments, a MEMS switch includes a first set of conductive contacts and a second set of conductive contacts. In the first stage of actuation, the movable beam contacts the first set of conductive contacts and a first conduction path is created. The first conduction path transmits a signal (e.g., a current at a low current level) that makes all conductive surfaces of the MEMS switch more equipotential. Thus, in the second stage of actuation, the electric fields and electrical currents exercised while the movable beam contacts both the first set of conductive contacts and the second set of conductive contacts are very much reduced, suppressing potential damage and the associated reliability implications. 
       FIG.  2 A  illustrates a vertical cross-sectional view of a second MEMS switch  200  in an open or off state in accordance with embodiments of the disclosure. The cross-sectional view of the second MEMS switch  200  is taken along a plane where movement of the movable beam  102  occurs. The second MEMS switch  200  includes the movable beam  102  that spans across the cavity  104 . The first attachment element  106  is used to attach the first end  108  of the movable beam  102  to the first anchor  110 . The second attachment element  112  is used to attach the second end  114  of the movable beam  102  to the second anchor  116 . 
     A first conductive contact  202  and a second conductive contact  204  are disposed under the movable beam  102 . The first conductive contact  202  and the second conductive contact  204  form a first set of conductive contacts  206 . A third conductive contact  208  and a fourth conductive contact  210  are disposed under the movable beam  102 . The third conductive contact  208  and the fourth conductive contact  210  form a second set of conductive contacts  212 . The first conductive contact  202 , the second conductive contact  204 , the third conductive contact  208 , and the fourth conductive contact  210  are each made of a conductive material, such as titanium, titanium nitride, titanium aluminum, titanium aluminum nitride, aluminum, tungsten, platinum, iridium, rhodium, ruthenium, ruthenium oxide, molybdenum, or indium tin oxide. Although  FIG.  2 A  shows four conductive contacts, other embodiments can include any number of conductive contacts. 
     The signal source  130  is operably connected to a first node  214 . The third conductive contact  208  and a first resistor  216  are also operably connected to the first node  214 . The first conductive contact  202  is operably connected to the first resistor  216 . Thus, the first conductive contact  202  and the third conductive contact  208  are both operably connected to the signal source  130 . 
     A second resistor  218  is operably connected between the second conductive contact  204  and a second node  220 . The fourth conductive contact  210  and the load  136  are operably connected to the second node  220 . The fourth conductive contact  210  is operably connected to the second node  220 . Thus, the second conductive contact  204  and the fourth conductive contact  210  are both operably connected to the load  136 . The load  136  is also operably connected to the reference voltage  134 . 
     The movable beam  102  is suspended over the first set of conductive contacts  206  and the second set of conductive contacts  212 . In the illustrated embodiment, the first set of conductive contacts  206  is positioned between the third conductive contact  208  and the fourth conductive contact  210 . The movable beam  102  is operable to bend or deform to contact the first set of conductive contacts  206  and the second set of conductive contacts  212 . As will be described in more detail in conjunction with  FIG.  2 B  and  FIG.  2 C , the second MEMS switch  200  will transition to a closed or an on state through a two-stage actuation process. 
     In  FIG.  2 A , the first conductive contact  202  and the second conductive contact  204  are formed to have a first height H 1 . The third conductive contact  208  and the fourth conductive contact  210  are formed to have a second height H 2 , where H 2  is less than H 1 . In other embodiments, the first conductive contact  202 , the second conductive contact  204 , the third conductive contact  208 , and the fourth conductive contact  210  may all be formed to have the same height (e.g., H 2 ). Due to the nature of the second MEMS switch  200 , the movable beam  102  flexes and first contacts the centrally located first conductive contact  202  and the second conductive contact  204  before contacting the third conductive contact  208  and the fourth conductive contact  210  (e.g., as shown in  FIG.  1 B ). 
       FIG.  2 B  illustrates the second MEMS switch  200  shown in  FIG.  2 A  activated and deformed to a point where the movable beam  102  contacts the first set of conductive contacts  206  in accordance with embodiments of the disclosure. To cause the movable beam  102  to bend downward, a power signal (e.g., a voltage signal) is applied to pull-down electrodes (not shown in  FIGS.  2 A- 2 C ) that are positioned in a substrate below the first set of conductive contacts  206  and/or the second set of conductive contacts  212 . When the power signal is applied across the pull-down electrodes, the pull-down electrodes electrostatically pull the movable beam  102  downward. 
     Since the first set of conductive contacts  206  are made of a conductive material, a first conduction path is formed between the signal source  130  and the load  136  when the movable beam  102  contacts the first set of conductive contacts  206 . In particular, the first conduction path is created from the signal source  130  to the first resistor  216 , from the first resistor  216  to the first conductive contact  202 , from the first conductive contact  202  to the movable beam  102 , from the movable beam  102  to the second conductive contact  204 , from the second conductive contact  204  to the second resistor  218 , and from the second resistor  218  to the load  136 . A first signal (e.g., an RF signal) begins to transmit through the second MEMS switch  200  along the first conduction path. A resistor symbol  222  represents an electrical resistance of the movable beam  102  as the first signal propagates along the movable beam  102 . 
       FIG.  2 C  illustrates the second MEMS switch  200  shown in  FIG.  2 B  activated and deformed to a point where the movable beam  102  contacts the first set of conductive contacts  206  and the second set of conductive contacts  212  in accordance with embodiments of the disclosure. As the power signal continues to be applied across the pull-down electrodes, the pull-down electrodes electrostatically pull the movable beam  102  down further until the movable beam  102  contacts both the first set of conductive contacts  206  and the second set of conductive contacts  212 . Since the second set of conductive contacts  212  are made of a conductive material, a second conduction path is created in the second MEMS switch  200  when the movable beam  102  contacts the second set of conductive contacts  212 . In particular, the second conduction path is created from the signal source  130  to the first node  214 , from the first node  214  to the third conductive contact  208 , from the third conductive contact  208  to the movable beam  102 , from the movable beam  102  to the fourth conductive contact  210 , from the fourth conductive contact  210  to the second node  220 , and from the second node  220  to the load  136 . A second signal (e.g., an RF signal) propagates through the second MEMS switch  200  along the second conduction path. The resistor symbols  224 ,  226  represent the electrical resistance of the movable beam  102  as the second signal propagates along the movable beam  102 . 
     The second MEMS switch  200  is shown in  FIG.  2 C  in the closed or on state. In the closed state, the first signal is routed from the signal source  130  to the load  136  along the first conduction path and the second signal is routed from the signal source  130  to the load  136  along the second conductive signal path. To open the second MEMS switch  200 , the reverse process is performed. The second MEMS switch  200  transitions to the first stage shown in  FIG.  2 B  and then transitions to the open state shown in  FIG.  2 A . 
     The signal source  130  generates a maximum available power P SRC  and the load  136  has an impedance Z L . In the open or off state shown in  FIG.  2 A , the second MEMS switch  200  isolates the signal source  130  from the load  136 . In the closed or on state shown in  FIG.  2 C , the second MEMS switch  200  provides low loss transmission of the signal between the signal source  130  and the load  136 . Therefore, a voltage across the second MEMS switch  200  in the off state is equal to the open-circuit voltage of the signal source, as shown in Equation 1. 
         V   OFF   =V   S =√{square root over (8 Z   L   P   SRC )}  Equation 1
 
     When the second MEMS switch  200  transitions from the off state in  FIG.  2 A  to the on state in  FIG.  2 C , the second MEMS switch  200  first reaches the first stage of actuation in  FIG.  2 B . As described earlier, the first conduction path between signal source  130  and the load  136  is established through the first resistor  216  and the second resistor  218  (each of value R PL ), and the first conductive contact  202  and the second conductive contact  204  (each of value R C1 ). The movable beam  102  generates the electrical resistance represented by the resistor  222  (of value R B1 ). The value of the first resistor  216 , the value of the electrical resistance (resistor  222 ), and the value of the second resistor  218  in series define a voltage drop across the second MEMS switch  200  that can be characterized by the following Equation: 
     
       
         
           
             
               
                 
                   
                     
                       V 
                       RED 
                     
                     = 
                     
                       
                         V 
                         OFF 
                       
                       ⁢ 
                       
                         
                           R 
                           SE 
                         
                         
                           
                             R 
                             SRC 
                           
                           + 
                           
                             R 
                             L 
                           
                           + 
                           
                             R 
                             SE 
                           
                         
                       
                     
                   
                   , 
                 
               
               
                 
                   Equation 
                   ⁢ 
                       
                   2 
                 
               
             
           
         
       
       
         
           
             
               where 
               ⁢ 
                   
               
                 R 
                 SE 
               
             
             = 
             
               
                 2 
                 ⁢ 
                 
                   R 
                   PL 
                 
               
               + 
               
                 2 
                 ⁢ 
                 
                   R 
                   
                     C 
                     ⁢ 
                     1 
                   
                 
               
               + 
               
                 R 
                 
                   B 
                   ⁢ 
                   1 
                 
               
             
           
         
       
     
     Both the signal source  130  and impedance of the load  136  are assumed real for simplicity. 
     The second MEMS switch  200  then reaches the second stage of actuation shown in  FIG.  2 C . In this configuration, the second conduction path is formed in parallel to the first conduction path. The second conduction path is through the third conductive contact  208  and the fourth conductive contact  210  (each of value R CNT ). The movable beam  102  generates the electrical resistances represented by the resistors  222 ,  224 ,  226  (resulting in a generalized beam resistance R BEAM ). The on state resistance of the second MEMS switch  200  may be defined by Equation 3: 
     
       
         
           
             
               
                 
                   
                     
                       R 
                       ON 
                     
                     = 
                     
                       
                         
                           R 
                           SE 
                         
                       
                       
                         
                           R 
                           SE 
                         
                         + 
                       
                     
                   
                   , 
                 
               
               
                 
                   Equation 
                   ⁢ 
                       
                   3 
                 
               
             
           
         
       
     
     where  =2R CNT +R BEAM  is the on state resistance of a MEMS switch that does not include the hot switch protection. In certain embodiments,  &lt;&lt;R SE  and therefore R ON ≈ , so the on state loss is not significantly different as a result of the introduction of the two-stage hot switch protection. 
     To quantify a level of protection that is achieved in the two-stage actuation in  FIGS.  2 A- 2 C , the reduction in voltage resulting from the second MEMS switch  200  at the first stage of actuation ( FIG.  2 B ) can be transformed in an equivalent source power assuming no such hot switching protection was in place. As a result, an equivalent power reduction coefficient can be obtained as a function of the total series resistance R SE  of the first resistor  216 , the electrical resistance represented by the resistor  222 , and the second resistor  218 . The voltage reduction, which is one mechanism in the improved hot switch reliability, is fundamentally related to the value of the total series resistance presented by the second MEMS switch  200  after completing the first stage of actuation ( FIG.  2 B ), where the first stage of actuation includes the first resistor  216  and the second resistor  218  (each of value R PL ), the first conductive contact  202  and the second conductive contact  204  (each of value R C1 ), and the electrical resistance represented by the resistor  222  of the movable beam  102  (value R B1 ). 
       FIG.  3    illustrates a cross-sectional view of a third MEMS switch  300  in accordance with embodiments of the disclosure. The third MEMS switch  300  includes a substrate  302 . A first pull-down electrode  304 , a second pull-down electrode  306 , a third pull-down electrode  308 , and a fourth pull-down electrode  310  are disposed at and/or on a surface  312  of the substrate  302 . A first conductor  314 , a second conductor  316 , a third conductor  318 , and a fourth conductor  320  are disposed in the substrate  302 . In certain embodiments, the first conductor  314 , the second conductor  316 , the third conductor  318 , and the fourth conductor  320  are RF conductors. The first conductive contact  202 , the second conductive contact  204 , the third conductive contact  208 , and the fourth conductive contact  210  are disposed on the surface  312  of the substrate  302 . 
     A first conductive via  322  operably (e.g., electrically) connects the first conductor  314  to a first contact pad  324 . The first contact pad  324  operably connects to the third conductive contact  208 . Thus, the first conductor  314  is operably connected to the third conductive contact  208 . 
     A second conductive via  326  operably connects the second conductor  316  to a second contact pad  328 . The second contact pad  328  is operably connected to the first conductive contact  202 . Thus, the second conductor  316  is operably connected to the first conductive contact  202 . 
     A third conductive via  330  operably connects the third conductor  318  to a third contact pad  332 . The third contact pad  332  is operably connected to the second conductive contact  204 . Thus, the third conductor  318  is operably connected to the second conductive contact  204 . 
     A fourth conductive via  334  operably connects the fourth conductor  320  to a fourth contact pad  336 . The fourth contact pad  336  is operably connected to the fourth conductive contact  210 . Thus, the fourth conductor  320  is operably connected to the fourth conductive contact  210 . 
     A movable beam  338  is suspended over the substrate  302 , the first conductive contact  202 , the second conductive contact  204 , the third conductive contact  208 , and the fourth conductive contact  210 . A first end  339  of the movable beam  338  is supported by a first attachment element  340  and a second end  341  of the movable beam  338  is supported by a second attachment element  342 . The first attachment element  340  and the second attachment element  342  may each include one or more layers. 
     The movable beam  338  includes a first beam contact  344 , a second beam contact  346 , a third beam contact  348 , and a fourth beam contact  350  that are each made of one or more conductive materials. The first beam contact  344  is aligned with the third conductive contact  208 . The second beam contact  346  is aligned with the first conductive contact  202 . The third beam contact  348  is aligned with the second conductive contact  204 . The fourth beam contact  350  is aligned with the fourth conductive contact  210 . When the movable beam  338  is in the first stage of actuation, the second beam contact  346  contacts the first conductive contact  202  and the third beam contact  348  contacts the second conductive contact  204 . When the movable beam  338  is in the second stage of actuation, the first beam contact  344  contacts the third conductive contact  208 , the second beam contact  346  contacts the first conductive contact  202 , the third beam contact  348  contacts the second conductive contact  204 , the fourth beam contact  350  contacts the fourth conductive contact  210 . 
       FIG.  4    illustrates a top view of a MEMS switch  400  in accordance with embodiments of the disclosure. The MEMS switch  400  includes a movable beam  402  suspended over a first set of conductive contacts  404 , a second set of conductive contacts  406 , and a third set of conductive contacts  408 . The first set of conductive contacts  404  includes a set of third conductive contacts  208 . The second set of conductive contacts  406  includes a set of the first conductive contact  202  and the second conductive contact  204 . The third set of conductive contacts  408  includes a set of fourth conductive contacts  210 . The first set of conductive contacts  404 , the second set of conductive contacts  406 , and the third set of conductive contacts  408  are shown in dashed lines because they are not visible in the top view. Although  FIG.  4    depicts three sets of conductive contacts, a MEMS switch can include one or more first conductive contacts  202 , one or more second conductive contacts  204 , one or more third conductive contacts  208 , and one or more fourth conductive contacts  210 . 
     The movable beam  402  can be configured as, or similar to, the movable beam  338  of  FIG.  3   . The movable beam  402  is held in suspension by a first attachment element  410  and a second attachment element  412 . Any suitable attachment element can be used for the first attachment element  410  and the second attachment element  412 . For example, the first attachment element  410  and the second attachment element  412  may be configured as springs ( FIG.  1   ). 
     Multiple MEMS switches can be coupled together.  FIG.  5    illustrates a top view of MEMS switches  400  mechanically and electrically connected together in accordance with embodiments of the disclosure. In the example embodiment, each pair of movable beams  402  is coupled together using a beam link  500 . As such, the movable beams  402  are coupled in parallel. The beam link  500  can be made of the same material, or at least some of the same materials, as the movable beams  402 . 
     A cell of MEMS switches can be created by coupling multiple MEMS switches together.  FIG.  6    illustrates a top view of a first cell  600  in accordance with embodiments of the disclosure. The first cell  600  includes multiple MEMS switches  400  electrically and mechanically coupled together by the beam link  500 . In the example embodiment, the first cell  600  includes eighteen ( 18 ) MEMS switches  400  coupled together in parallel. Other embodiments are not limited to this configuration. 
     A first conductor  602  and a second conductor  604  are disposed transverse (e.g., perpendicular) to the movable beams  402  and in parallel below the MEMS switches  400  in the first cell  600 . In certain embodiments, the first conductor  602  and the second conductor  604  are RF conductors. Conductive vias (e.g., the fourth conductive vias  334  in  FIG.  3   ) are used to connect the fourth conductive contacts  210  in the third set of conductive contacts  408  to the first conductor  602 . Conductive vias (e.g., the first conductive vias  322  in  FIG.  3   ) are used to connect the third conductive contacts  208  in the first set of conductive contacts  404  to the second conductor  604 . Based on this configuration, one can appreciate how all of the MEMS switches  400  in the first cell  600  are connected in parallel. Accordingly, the on state resistance of the entire first cell  600  is equal to (or substantially equal to) that of a single MEMS switch  400  divided by N, where N represents the number of MEMS switches  400  in the first cell  600 . 
       FIG.  7    illustrates a top view of a second cell  700  in accordance with embodiments of the disclosure.  FIG.  7    is similar to  FIG.  6   , and further depicts a first group of first stage actuation contacts  702  and a second group of first stage actuation contacts  704 . The first group of first stage actuation contacts  702  are included in the MEMS switch  400 A. The first group of first stage actuation contacts  702  includes the second set of conductive contacts  406  electrically connected to the first set of conductive contacts  404 . The third conductive contacts  208 A,  208 B in the first set of conductive contacts  404  are operably (e.g., electrically) connected to the second conductor  604 . Additionally, the first conductive contacts  202 A,  202 B in the second set of conductive contacts  406  are also operably connected to the second conductor  604 . In certain embodiments, all of the conductive contacts in the first set of conductive contacts  404  (including the third conductive contacts  208  (e.g.,  208 A,  208 B,  208 C,  208 D)) in the second cell  700  are operably connected to the second conductor  604  and some, but not all, of the first conductive contacts  202  (e.g.,  202 A,  202 B) in the second cell  700  are operably connected to the second conductor  604  (e.g., in MEMS switch  400 A). 
     The second group of first stage actuation contacts  704  are included in a different MEMS switch  400 B. The second group of first stage actuation contacts  704  includes a second set of conductive contacts  406  operably connected to the third set of conductive contacts  408 . The fourth conductive contacts  210 C,  210 D in the third set of conductive contacts  408  are operably connected to the first conductor  602  and the second conductive contacts  204 C,  204 D are operably connected to the first conductor  602 . In certain embodiments, all of the conductive contacts in the third set of conductive contacts  408  (including the fourth conductive contacts  210  (e.g.,  210 A,  210 B,  210 C,  210 D)) in the second cell  700  are operably connected to the first conductor  602  and some, but not all, of the second conductive contacts  204  (e.g.,  204 C,  204 D) in the second cell  700  are operably connected to the first conductor  602  (e.g., in MEMS switch  400 B). 
     The portions of the movable beams  402  located between the first group of first stage actuation contacts  702  and the second group of first stage actuation contacts  704  form a movable beam section  706 . When the second cell  700  is actuated to the first stage of actuation, the first conduction path is established within the second cell  700 . The first conduction path includes the first group of first stage actuation contacts  702 , the electrical resistance (represented by a resistor) of the movable beam section  706 , and the second group of first stage actuation contacts  704 . In general, due to the lack of parallelization in the first conduction path, the value of the total reduction resistance R RED  can be higher than the on state cell resistance R ON , but the actual value is a function of: the first and the second groups of first stage actuation contacts  702 ,  704 ; the resistivity of the material in the movable beam  402 ; and the geometry of the movable beams  402 . 
       FIG.  8 A  illustrates a vertical cross-sectional view of a portion of the MEMS switch  400 A taken along line  8 A- 8 A in  FIG.  7    in accordance with embodiments of the disclosure. The MEMS switch  400 A includes the third conductive contact  208 A, the fourth conductive contact  210 A, and the first conductive contact  202 A positioned between the third conductive contact  208 A and the fourth conductive contact  210 A. The movable beam  402  with the first beam contact  344 A, the second beam contact  346 A, and the fourth beam contact  350 A is suspended over the substrate  302  and the first conductive contact  202 A, the third conductive contact  208 A, and the fourth conductive contact  210 A. 
     The fourth conductive contact  210 A is operably connected to the first conductor  602  in the substrate  302  through the fourth conductive via  334 A and the fourth contact pad  336 A. The third conductive contact  208 A is operably connected to the second conductor  604  in the substrate  302  through the first conductive via  322 A and the first contact pad  324 A. The first conductive contact  202 A is operably connected to the second conductor  604  in the substrate  302  through the second conductive via  326 A and the second contact pad  328 A. Thus, both the first conductive contact  202 A and the third conductive contact  208 A are operably connected to the second conductor  604  and to each other through the second conductor  604 . 
       FIG.  8 B  illustrates a vertical cross-sectional view of a portion of the MEMS switch  400 B taken along line  8 B- 8 B in  FIG.  7    in accordance with embodiments of the disclosure. The MEMS switch  400 B includes the third conductive contact  208 C, the fourth conductive contact  210 C, and the second conductive contact  204 C positioned between the third conductive contact  208 C and the fourth conductive contact  210 C. The movable beam  402  with the first beam contact  344 C, the third beam contact  348 C, and the fourth beam contact  350 C is suspended over the substrate  302 , the third conductive contact  208 C, the second conductive contact  204 C, and the fourth conductive contact  210 C. 
     The third conductive contact  208 C is operably connected to the second conductor  604  in the substrate  302  through the first conductive via  322 C and the first contact pad  324 D. The second conductive contact  204 C is operably connected to the first conductor  602  in the substrate  302  through the third conductive via  330 C and the third contact pad  332 C. The fourth conductive contact  210 C is operably connected to the first conductor  602  in the substrate  302  through the fourth conductive via  334 C and the fourth contact pad  336 C. Thus, both the second conductive contact  204 C and the fourth conductive contact  210 C are operably connected to the first conductor  602  and to each other through the first conductor  602 . 
       FIG.  9    illustrates a top view of a third cell  900  in accordance with embodiments of the disclosure. The third cell  900  includes multiple MEMS switches  400  electrically and mechanically coupled together by the beam link  500 . In the example embodiment, the third cell  900  includes eighteen ( 18 ) MEMS switches  400  coupled together in parallel. Other embodiments are not limited to this configuration. 
     The first conductor  602  and the second conductor  604  are disposed traverse to (e.g., perpendicular to) the movable beams  402  and in parallel below the MEMS switches  400 . Conductive vias (e.g., the fourth conductive vias  334  in  FIG.  3   ) are used to connect the fourth conductive contacts  210  in the third set of conductive contacts  408  to the first conductor  602 . Conductive vias (e.g., the first conductive vias  322  in  FIG.  3   ) are used to connect the third conductive contacts  208  in the first set of conductive contacts  404  to the second conductor  604 . 
     The third cell  900  further includes multiple first groups of first stage actuation contacts  702 A,  702 B,  702 C in MEMS switches  400 A and multiple second groups of first stage actuation contacts  704 A,  704 B,  704 C in MEMS switches  400 B. In the example embodiment, the first groups of first stage actuation contacts  702 A,  702 B,  702 C are interposed between the second groups of first stage actuation contacts  704 A,  704 B,  704 C. The first groups of first stage actuation contacts  702 A,  702 B,  702 C and the second groups of first stage actuation contacts  704 A,  704 B,  704 C may be arranged differently in other embodiments. 
     When the third cell  900  is actuated to the first stage of actuation, first conduction paths are established within the third cell  900 . The first conduction paths resulting from each pair of adjacent first and second groups of first stage actuation contacts  702 A+ 704 A,  702 B+ 704 B,  702 C+ 704 C,  702 B+ 704 A, and  702 C+ 704 B are in parallel, and the total resistance will be reduced by a factor K, where K represents the number of the pairs of adjacent first and second groups of first stage actuation contacts (e.g.,  702 A+ 704 A,  702 B+ 704 B,  702 C+ 704 C,  702 B+ 704 A, and  702 C+ 704 B). 
     Similar to  FIG.  7   , all of the conductive contacts in the first set of conductive contacts  404  (including the third conductive contacts  208  (e.g.,  208 A,  208 B,  208 C,  208 D)) in the third cell  900  are operably connected to the second conductor  604  and some, but not all, of the first conductive contacts  202  (e.g.,  202 A,  202 B) in the third cell  900  are operably connected to the second conductor  604  (e.g., in MEMS switches  400 A). All of the conductive contacts in the third set of conductive contacts  408  (including the fourth conductive contacts  210  (e.g.,  210 A,  210 B,  210 C,  210 D)) in the third cell  900  are operably connected to the first conductor  602  and some, but not all, of the second conductive contacts  204  (e.g.,  204 C,  204 D) in the third cell  900  are operably connected to the first conductor  602  (e.g., in MEMS switches  400 B). 
     In some instances, a higher resistive path is desired in the first actuation stage.  FIG.  10    illustrates a top view of a fourth cell  1000  in accordance with embodiments of the disclosure. The fourth cell  1000  is similar to the second cell  700  shown in  FIG.  7    with the addition of one or more series resistors. In the example embodiment, the one or more series resistors are first series resistor  1002  and second series resistor  1004 . The first series resistor  1002  includes a third resistor  1006  operably connected between a respective conductive contact in the first set of conductive contacts  404  and a corresponding conductive contact the second set of conductive contacts  406 . For example, the third resistor  1006  is operably connected between the third conductive contacts  208 A,  208 B and the first conductive contacts  202 A,  202 B in the first group of first stage actuation contacts  702 . The third resistor  1006  is included in a sequence of MEMS switches  400  (e.g., MEMS switches  400  next to each other) such that multiple third resistors  1006  are connected in series to produce the first series resistor  1002 . 
     The second series resistor  1004  includes a fourth resistor  1008  operably connected between a respective conductive contact in the second set of conductive contacts  406  and a corresponding conductive contact in the third set of conductive contacts  408 . For example, a fourth resistor  1008  is operably connected between the second conductive contacts  204 C,  204 D and the fourth conductive contacts  210 C,  210 D in the second group of first stage actuation contacts  704 . The fourth resistor  1008  is included in a sequence of MEMS switches  400  (e.g., MEMS switches  400  next to each other) such that multiple fourth resistors  1008  are connected in series to produce the second series resistor  1004 . 
     The first group of first stage actuation contacts  702  of the MEMS switch  400 A is operably connected to the second conductor  604  through the first series resistor  1002 . The second group of first stage actuation contacts  704  of the MEMS switch  400 B is operably connected to the first conductor  602  through the second series resistor  1004 . In this manner, the first series resistor  1002  and the second series resistor  1004  increase the resistance of the first conduction path. 
     The first series resistor  1002  and the second series resistor  1004  can be implemented using standard semiconductor fabrication processes such as doped polysilicon or other conductive materials, with different levels of resistivity (low resistivity or high resistivity). The resistivity and the geometry of the conductive materials (e.g., polysilicon) define the level of resistivity, thereby giving a designer the freedom to set the value of the resistance. When the fourth cell  1000  is actuated to the first stage of actuation, the first conduction path within the fourth cell  1000  is established through the first and the second groups of first stage actuation contacts  702 ,  704 , the first and the second series resistors  1002 ,  1004 , and the resistance of the movable beam section  706 . In general, due to the lack of parallelization in the first conduction path, the value of the total reduction resistance R RED  can be higher than the on state cell resistance RON, but the actual value is a function of: the resistances of the first and the second groups of first stage actuation contacts  702 ,  704 ; the resistivity of the material in the movable beam  402 ; the geometry of the movable beam  402 ; the resistivity of the material in first and the second series resistors  1002 ,  1004 ; and the geometry of the first and the second series resistors  1002 ,  1004 . 
       FIG.  11 A  illustrates a vertical cross-sectional view of a portion of the MEMS switch  400 A taken along line  11 A- 11 A in  FIG.  10    in accordance with embodiments of the disclosure. The MEMS switch  400 A is similar to the MEMS switch  400 A in  FIG.  8 A , with the addition of the first series resistor  1002  in a second substrate  1100  that is attached to the first substrate  302 . A fifth conductive via  1102  operably (e.g., electrically) connects the second conductor  604  to the first series resistor  1002 . A sixth conductive via  1104  operably connects a third conductor  1106  to the first series resistor  1002 . In certain embodiments, the third conductor  1106  is an RF conductor. Thus, the first series resistor  1002  is included in the first conduction path when the MEMS switch  400 A is actuated to the first stage of actuation. 
     In certain embodiments, all of the conductive contacts in the first set of conductive contacts  404  (including the third conductive contacts  208  (e.g.,  208 A,  208 B,  208 C,  208 D)) are operably connected to the second conductor  604  and some, but not all, of the first conductive contacts  202  (e.g.,  202 A,  202 B) are operably connected to the third conductor  1106  (e.g., in MEMS switch  400 A). Accordingly, all of the conductive contacts in the first set of conductive contacts  404  (including the third conductive contacts  208 ) are operably connected to the first series resistor  1002  and some, but not all, of the first conductive contacts  202  are operably connected to the first series resistor  1002 . 
       FIG.  11 B  illustrates a vertical cross-sectional view of a portion of the MEMS switch  400 B taken along line  11 B- 11 B in  FIG.  10    in accordance with embodiments of the disclosure. The MEMS switch  400 B is similar to the MEMS switch  400 B in  FIG.  8 B , with the addition of the second series resistor  1004  in the second substrate  1100 . A seventh conductive via  1108  operably (e.g., electrically) connects the first conductor  602  to the second series resistor  1004 . An eighth conductive via  1110  operably connects a fourth conductor  1112  to the second series resistor  1004 . In certain embodiments, the fourth conductor  1112  is an RF conductor. Thus, the second series resistor  1004  is included in the first conduction path when the MEMS switch  400 B is actuated to the first stage of actuation. 
     In certain embodiments, all of the conductive contacts in the third set of conductive contacts  408  (including the fourth conductive contacts  210  (e.g.,  210 A,  210 B,  210 C,  210 D)) are operably connected to the first conductor  602  and some, but not all, of the second conductive contacts  204  (e.g.,  204 C,  204 D) are operably connected to the fourth conductor  1112  (e.g., in MEMS switch  400 B). Accordingly, all of the conductive contacts in the third set of conductive contacts  408  (including the fourth conductive contacts  210 ) are operably connected to the second series resistor  1004  and some, but not all, of the second conductive contacts  204  are operably connected to the second series resistor  1004 . 
       FIG.  12    illustrates a top view of a fifth cell  1200  in accordance with embodiments of the disclosure. The fifth cell  1200  is similar to the fourth cell  1000 , but with the first series resistor  1002  and the second series resistor  1004  extending under multiple MEMS switches  400 A- 400 P in the fifth cell  1200 . Multiple first groups of first stage actuation contacts  702  are operably connected to the second conductor  604  and to the first series resistor  1002 . Multiple second groups of first stage actuation contacts  704  are operably connected to the first conductor  602  and to the second series resistor  1004 . Although not shown in  FIG.  12   , the fifth cell  1200  includes the third resistors  1006  and the fourth resistors  1008  shown in  FIG.  10   . 
     The portions of the movable beams  402  located between each pair of first group of first stage actuation contacts  702 A,  702 B,  702 C and second group of first stage actuation contacts  704 A,  704 B,  704 C form movable beam sections  706 A,  706 B,  706 C,  706 D,  706 E. In the illustrated embodiment, the movable beam section  706 A is established between the first group of first stage actuation contacts  702 A and the second group of first stage actuation contacts  704 A. The movable beam section  706 B is established between the second group of first stage actuation contacts  704 A and the first group of first stage actuation contacts  702 B. The movable beam section  706 C is established between the first group of first stage actuation contacts  702 B and the second group of first stage actuation contacts  704 B. The movable beam section  706 D is established between the second group of first stage actuation contacts  704 B and the first group of first stage actuation contacts  702 C. The movable beam section  706 E is established between the first group of first stage actuation contacts  702 C and the second group of first stage actuation contacts  704 C. 
     When the fifth cell  1200  is actuated to the first stage of actuation, a first conduction path within the fifth cell  1200  is created through the first groups of first stage actuation contacts  702 A,  702 B,  702 C, the second groups of first stage actuation contacts  704 A,  704 B,  704 C, the first series resistor  1002 , the second series resistor  1004 , and the movable beam sections  706 A- 706 E of the movable beams  402  that are connected in parallel. The current inrush in each of the individual first stage conductive contacts (e.g., the first conductive contact  202  and the second conductive contact  204 ) is reduced by a factor of K compared to the embodiment shown in  FIG.  10   . 
     Similar to  FIGS.  10 - 11 B , all of the conductive contacts in the first set of conductive contacts  404  (including the third conductive contacts  208  (e.g.,  208 A,  208 B,  208 C,  208 D)) are operably connected to the second conductor  604  and some, but not all, of the first conductive contacts  202  (e.g.,  202 A,  202 B) are operably connected to the third conductor  1106  (e.g., in MEMS switches  400 A,  400 C,  400 M). Accordingly, all of the conductive contacts in the first set of conductive contacts  404  (including the third conductive contacts  208 ) are operably connected to the first series resistor  1002  and some, but not all, of the first conductive contacts  202  are operably connected to the first series resistor  1002 . All of the conductive contacts in the third set of conductive contacts  408  (including the fourth conductive contacts  210  (e.g.,  210 A,  210 B,  210 C,  210 D)) are operably connected to the first conductor  602  and some, but not all, of the second conductive contacts  204  (e.g.,  204 C,  204 D) are operably connected to the fourth conductor  1112  (e.g., in MEMS switches  400 B,  400 F,  400 P). Accordingly, all of the conductive contacts in the third set of conductive contacts  408  (including the fourth conductive contacts  210 ) are operably connected to the second series resistor  1004  and some, but not all, of the second conductive contacts  204  are operably connected to the second series resistor  1004 . 
       FIG.  13    illustrates a method of operating a MEMS switch in accordance with embodiments of the disclosure. The method is described in conjunction with a single MEMS switch, but the method can be used concurrently with multiple MEMS switches. The method includes operations to close a MEMS switch  1300  and to open a MEMS switch  1302 . 
     Initially, the MEMS switch is in an open or off state and actuation of the MEMS switch begins (block  1304 ). As described earlier, a power signal (e.g., a voltage signal) is applied to pull-down electrodes to initiate and maintain the activation of the MEMS switch. The first conduction path is established at block  1306 . As described earlier, the first conduction path is created when the movable beam in the MEMS switch deforms to a first point to contact the first set of conductive contacts in the MEMS switch (e.g., the first conductive contact  202  and the second conductive contact  204 ). At the first point, the MEMS switch is in a partially closed state. 
     After the first conduction path is established, actuation of the MEMS switch continues at block  1308 . The actuation of the MEMS switch continues by maintaining the application of the power signal on the pull-down electrodes. The second conduction path is created at block  1310 . As described previously, the second conduction path is established when the movable beam deforms to a second point to contact both the first set of conductive contacts and the second set of conductive contacts (e.g., the third conductive contact  208  and the fourth conductive contact  210 ) in the MEMS switch. At the second point, the MEMS switch is in an on or closed state. 
     To open the MEMS switch  1302 , actuation of the MEMS switch ends and the MEMS switch transitions to a partially open state (block  1312 ). In the partially open state, the movable beam begins to straighten (e.g., unbend) such that the movable beam does not contact the second set of conductive contacts. Thereafter, the MEMS switch transitions to the open or off state (block  1314 ). In the open state, the movable beam does not contact both the first set of conductive contacts and the second set of conductive contacts. 
     It is contemplated that any of the foregoing aspects, and/or various separate aspects and features as described herein, may be combined for additional advantage. Any of the various embodiments as disclosed herein may be combined with one or more other disclosed embodiments unless indicated to the contrary herein. 
     Those skilled in the art will recognize improvements and modifications to the preferred embodiments of the present disclosure. All such improvements and modifications are considered within the scope of the concepts disclosed herein and the claims that follow.