“…A compact and simple controllable tunable bandpass filter has been fabricated based on a lumped–distributed transmission line filter concept [24] to select discretely the specific center frequency (from 20 to 23 GHz) with an independent controllable channel bandwidth (of approximately 0.5–1 GHz).…”
“…They work in analog continuous mode and its main function is to continuously tune the bandwidth of the bandpass filter by modifying the value of the coupling series- analog capacitor placed at both the input and the output of the filter. In addition, they can be used to fine de-tune the filter center frequency by an extra correcting element originally placed at the center of the filter and first introduced by the authors in [24]. Fig.…”
“…21(a)). Tuning of the bandwidth is also demonstrated in a constant center frequency, thanks to action of the correcting element [24]. A 13.6% of bandwidth tuning is achieved at 20.5 GHz center frequency with a 1 dB fractional bandwidth varying from 17 to 20%.…”
“…A wideband high-frequency tunable band-stop filter working in the Ku- to Ka-band frequencies was originally devised [14, 26]. The filter is based on a miniature single-MEM device combining a central capacitive MEM switch loaded in a CPW line and suspension arms designed as multiple inductive meanders with voltage-controlled coupling to the substrate (Fig.…”
This paper reports on the potential of RF-MEMS technology based on aluminum nitride capacitive dielectric and nickelsuspended membranes to provide RF circuit functions in reconfigurable front-end radios. The RF performance of capacitive switches, distributed MEMS transmission lines (DMTLs) phase shifters for beam steering and tunable filters, including center frequency and bandwidth tuning of bandpass and band-stop filters are presented. Detailed characterization based on S-parameter data demonstrates very promising figures of merit of all fabricated demonstrators from 5 to 40 GHz.Keywords: RF MEMS switch, phase shifter, tunable filter, modelling, simulation and characterization of devices and systems
I . I N T R O D U C T I O NIn the last half-century, RF-MEMS switches have been extensively studied as they accomplish superior RF performance and higher linearity than semiconductor junction switches such as Positive-Intrinsic-Negative (PIN) diodes or Fieldeffect transistor (FETs) [1]. Despite their higher control voltages compared to some solid-state switches, electrostatic-actuated Micro-electro-mechanical-systems (MEMS) offer significant power savings as well as potential lower cost and the capability of miniaturization which result in attractiveness for their use in wireless applications.In reconfigurable front-end RF ICs, functions like RF switching, filtering, and phase shifting in reflector array antennas for beam steering/forming networks (as illustrated in Fig. 1), can be realized with RF-MEMS components and systems using the same technology in a single fabrication process. RF MEMS offer new possibilities for improved performance and allow higher density and capacity of the overall systems.In this paper we present capacitive shunt switches in terms of performance as well as their applications as phase shifters and tunable filters. In Section II, the state of the art of capacitive switches is studied and compared with different fabricated switch designs including those based on analog and digital capacitor concepts and switches with highly inductive components that were specifically designed as core devices for the applications presented in the subsequent sections. Then, in Section III analog and 2-bit digital true time delay (TTD) phase shifters are described as well as the co-integration of phase shifters and the dipole antennas for beam steering applications. Finally, tunable filters with different functionalities, as bandpass and band-stop filter configurations are shown in Section IV.
I I . R F -M E M S C A P A C I T I V E S W I T C H › S W I T C H I N G
A) ClassificationCapacitive switches are mainly divided into two subcategories depending on their different functionalities; the RF-MEMS capacitive switch or analog MEMS capacitor, with high isolation and an increased capacitance ratio, Cr (.30) and the MEMS switch capacitor or digital MEMS capacitor with a moderate and usually defined Cr , 5. Analog MEMS capacitors can be used for signal routing purposes, in reconfigurable front-ends, digitized capa...
“…A compact and simple controllable tunable bandpass filter has been fabricated based on a lumped–distributed transmission line filter concept [24] to select discretely the specific center frequency (from 20 to 23 GHz) with an independent controllable channel bandwidth (of approximately 0.5–1 GHz).…”
“…They work in analog continuous mode and its main function is to continuously tune the bandwidth of the bandpass filter by modifying the value of the coupling series- analog capacitor placed at both the input and the output of the filter. In addition, they can be used to fine de-tune the filter center frequency by an extra correcting element originally placed at the center of the filter and first introduced by the authors in [24]. Fig.…”
“…21(a)). Tuning of the bandwidth is also demonstrated in a constant center frequency, thanks to action of the correcting element [24]. A 13.6% of bandwidth tuning is achieved at 20.5 GHz center frequency with a 1 dB fractional bandwidth varying from 17 to 20%.…”
“…A wideband high-frequency tunable band-stop filter working in the Ku- to Ka-band frequencies was originally devised [14, 26]. The filter is based on a miniature single-MEM device combining a central capacitive MEM switch loaded in a CPW line and suspension arms designed as multiple inductive meanders with voltage-controlled coupling to the substrate (Fig.…”
This paper reports on the potential of RF-MEMS technology based on aluminum nitride capacitive dielectric and nickelsuspended membranes to provide RF circuit functions in reconfigurable front-end radios. The RF performance of capacitive switches, distributed MEMS transmission lines (DMTLs) phase shifters for beam steering and tunable filters, including center frequency and bandwidth tuning of bandpass and band-stop filters are presented. Detailed characterization based on S-parameter data demonstrates very promising figures of merit of all fabricated demonstrators from 5 to 40 GHz.Keywords: RF MEMS switch, phase shifter, tunable filter, modelling, simulation and characterization of devices and systems
I . I N T R O D U C T I O NIn the last half-century, RF-MEMS switches have been extensively studied as they accomplish superior RF performance and higher linearity than semiconductor junction switches such as Positive-Intrinsic-Negative (PIN) diodes or Fieldeffect transistor (FETs) [1]. Despite their higher control voltages compared to some solid-state switches, electrostatic-actuated Micro-electro-mechanical-systems (MEMS) offer significant power savings as well as potential lower cost and the capability of miniaturization which result in attractiveness for their use in wireless applications.In reconfigurable front-end RF ICs, functions like RF switching, filtering, and phase shifting in reflector array antennas for beam steering/forming networks (as illustrated in Fig. 1), can be realized with RF-MEMS components and systems using the same technology in a single fabrication process. RF MEMS offer new possibilities for improved performance and allow higher density and capacity of the overall systems.In this paper we present capacitive shunt switches in terms of performance as well as their applications as phase shifters and tunable filters. In Section II, the state of the art of capacitive switches is studied and compared with different fabricated switch designs including those based on analog and digital capacitor concepts and switches with highly inductive components that were specifically designed as core devices for the applications presented in the subsequent sections. Then, in Section III analog and 2-bit digital true time delay (TTD) phase shifters are described as well as the co-integration of phase shifters and the dipole antennas for beam steering applications. Finally, tunable filters with different functionalities, as bandpass and band-stop filter configurations are shown in Section IV.
I I . R F -M E M S C A P A C I T I V E S W I T C H › S W I T C H I N G
A) ClassificationCapacitive switches are mainly divided into two subcategories depending on their different functionalities; the RF-MEMS capacitive switch or analog MEMS capacitor, with high isolation and an increased capacitance ratio, Cr (.30) and the MEMS switch capacitor or digital MEMS capacitor with a moderate and usually defined Cr , 5. Analog MEMS capacitors can be used for signal routing purposes, in reconfigurable front-ends, digitized capa...
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