On-state Insertion Loss Research Articles

Enhanced Robustness of a Bridge-Type Rf-Mems Switch for Enabling Applications in 5G and 6G Communications.

In this paper, new suspended-membrane double-ohmic-contact RF-MEMS switch configurations are proposed. Double-diagonal (DDG) beam suspensions, with either two or three anchoring points, are designed and optimized to minimize membrane deformation due to residual fabrication stresses, thus exhibiting smaller mechanical deformation and a higher stiffness with more release force than previously designed single diagonal beam suspensions. The two-anchor DDGs are designed in two different orientations, in-line and 90°-rotated. The membrane may include a window to minimize the coupling to the lower electrode. The devices are integrated in a coplanar-waveguide transmission structure and fabricated using an eight-mask surface-micro-machining process on high-resistivity silicon, with dielectric-free actuation electrodes, and including glass protective caps. The RF-MEMS switch behavior is assessed from measurements of the device S parameters in ON and OFF states. The fabricated devices feature a measured pull-in voltage of 76.5 V/60 V for the windowed/not-windowed two-anchor DDG membranes, and 54 V/49.5 V for the windowed/not-windowed three-anchor DDG membranes, with a good agreement with mechanical 3D simulations. The measured ON-state insertion loss is better than 0.7 dB/0.8 dB and the isolation in the OFF state is better than 40 dB/31 dB up to 20 GHz for the in-line/90°-rotated devices, also in good agreement with 2.5D electromagnetic simulations.

THz MEMS Switch Design

In this work, an mm-wave/THz MEMS switch design process is presented. The challenges and solutions associated with the switch electrical design, modeling, fabrication, and test are explored and discussed. To investigate the feasibility of this design process, the switches are designed on both silicon and fused quartz substrate and then tested in the 140–750 GHz frequency range. The measurement fits design expectations and simulation well. At 750 GHz the measurement results from switches on both substrates have an ON state insertion loss of less than 3 dB and an OFF state isolation larger than 12 dB.

Conductive Bridging-Based Memristive RF Switches on a Silicon Substrate

Three RF switches and a phase shifter are proposed using the conductive bridging random access memory (CBRAM) technique. The fabrication process is developed with the Nafion membrane on a high-resistivity silicon substrate. The equivalent circuit model is established for each memristive RF switch. The proposed switches and the phase shifter have been validated by the good agreement achieved among the simulated, measured, and modeled results. The experimental results show that the series planar switch has the ON-state insertion loss (IL) below 1.69 dB and the OFF-state isolation over 25 dB up to 10 GHz, with the actuation voltages of 6.1~7.8/-1.5~-2 V. The parallel metal-insulator-metal (MIM) switch has the small ON-state IL below 0.45 dB and the OFF-state isolation over 18.4 dB when biased with 0.8~3.7/-0.5~-0.9 V. The series MIM switch has the ON-state IL below 0.61 dB and the OFF-state isolation over 21.9 dB with 0.7~2.3/-0.5~-0.9 V. The series MIM switch shows a good comprehensive performance of low actuation voltage, good uniformity, low IL, moderate isolation, and independent control. The phase shifter is realized with four series MIM switches, which provides a phase shift of 45° ± 5° from 3.8 to 4.3 GHz with the in-band IL of 2.25 dB. Compared with the conventional RF switchable devices, the proposed devices have the advantages of nonvolatility and low power consumption. Without depending on the electron beam lithography process and high-temperature phase change, the proposed technique is promising for reconfigurable RF circuits with mass production and feasibility to various substrates.

Design of a Compact Dual-Band Absorptive Single-Pole Double-Throw Switch

In this letter, a compact dual-band absorptive single-pole double-throw (SPDT) switch design is proposed. It utilizes the bridged-T coil as a miniaturized dual-band <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda /4$ </tex-math></inline-formula> transformer such that the concurrent dual-band operation in the on-state and the desired absorptive property in the off-state can be both achieved. The proposed design concept is validated through a 2.45/5.8-GHz dual-band absorptive SPDT switch design implemented in a commercial GaAs pHEMT process. The measured on-state insertion loss is 1.54/1.97 dB and the off-state isolation is 35/29 dB at 2.45/5.8 GHz, while the measured return losses at all ports are better than 20 dB at 2.45/5.8 GHz. In addition, a compact chip size of 2.0 mm <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\times $ </tex-math></inline-formula> 1.5 mm is achieved.

A Photogenerated Silicon Plasma Waveguide Switch and Variable Attenuator for Millimeter-Wave Applications

This article reports the design, fabrication, and measurement of a millimeter-wave (mm-wave) solid-state <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\pi $ </tex-math></inline-formula> -match waveguide switch using bulk silicon micromachining. A photogenerated plasma within a silicon post is utilized as the switching element within the waveguide channel. Not only does this isolate the switch bias network from the RF signal path but also allows for tuning of the OFF-state isolation with increasing optical power for application as a variable attenuator. A measured OFF-state isolation greater than 25 dB up to 40 GHz is reported, with a measured extracted ON-state insertion loss of 0.52 dB at 35 GHz, and less than 0.88 dB across the entire band from 30 to 40 GHz. The proposed switch illustrates the significant potential for photogenerated silicon plasma switching of high-performance bulk micromachined mm-wave waveguides.

A broadband contactless gap waveguide microwave switch for X- and Ku-bands applications

This paper presents a novel wideband gap waveguide mechanical switch for low-loss and high-power radar and satellite applications. The proposed design has contactless waveguide structures and therefore the different conducting layers are not required to make physical contact joints. This property can make the structure more flexible and simple to fabricate than hollow waveguides at millimeter-waves and does not require high-precision fabrication or mechanical assembly such as diffusion bonding of laminated thin metal plates. The simulation and measurement results of the proposed switch show that the input reflection coefficient (|S11|) is less than −20 dB and the ON-state insertion loss (|S21|) is less than 0.1 dB, within the switch operational frequency bandwidth from 10.6 to 16 GHz. Also, the measured adjacent ports isolation for the OFF-state is greater than 75 dB over the desired frequency range. The measured and simulated results agree very well.

Optically-reconfigurable phase change material nanoantenna-embedded metamaterial waveguide

Heterogeneous integration of phase change materials (PCM) into photonic integrated circuits is of current interest for all-optical signal processing and photonic in-memory computing. The basic building block consists of waveguides or resonators embedded with state-switchable PCM cells evanescently coupled to the optical mode. Despite recent advances, further improvements are desired in performance metrics like switching speeds, switching energies, device footprint, and fan-out. We propose an architecture using resonant metamaterial waveguides loaded with Ge2Sb2Te5 (GST) nanoantenna, and present a numerical study of its performance. Our proposed design is predicted to have a write energy of 16 pJ, an erase energy of 190 pJ (which is three to four times lower than previous reports), and, an order of magnitude improvement in the write-process figure-of-merit. Additional advantages include lowered ON state insertion loss and GST volume reduction.

11 Gb/s 140 GHz OOK modulator with 24.6 dB isolation utilising cascaded switch and amplifier‐based stages in 65 nm bulk CMOS

This study presents a complementary metal-oxide-semiconductor (CMOS) 140 GHz on-off-keying (OOK) modulator with high isolation and low ON-state insertion loss based on a cascaded architecture of a switch-based and amplifier-based modulators. A prototype implemented in a 65 nm bulk CMOS process operates at 140 GHz carrier input and realises 24.6 dB isolation, whereas in ON-state it achieves 0.3 dB gain and -0.2 dBm OP1 dB with 8 mW power consumption. Up to 11 Gb/s modulation is verified with the spectrum and demodulated waveform measurements. The proposed OOK modulator occupies the core area of 250×380 μm 2 .

Compact Low-Loss Electroabsorption Modulator Using a Graphene-Inserted Metal-Slot-Added Waveguide

Metal slots have been used to obtain strong light-graphene interaction, which usually requires them to be a few tens of nanometers wide. However, narrow metal slot waveguides have a large intrinsic loss; they are not efficiently connected to conventional silicon photonic waveguides; they are not easy to fabricate. To address the issues, a graphene-inserted metal-slot-added (GIMSA) waveguide and an electroabsorption modulator (EAM) based on it are theoretically investigated. The GIMSA waveguide consists of a silicon strip embedded in silicon dioxide and a metal slot aligned above the silicon strip with double graphene layers between them. The EAM is composed of the GIMSA waveguide and input and output couplers connecting it to silicon photonic waveguides. In order to achieve the good performance of the EAM in terms of length and insertion loss, the GIMSA waveguide and the couplers are designed. When the silicon strip and the metal slot are respectively 320 nm and 316 nm wide, the total length of the EAM with an extinction ratio of 3 dB is 6.23 μm, and its on-state insertion loss is 1.01 dB. Compared to previous graphene-based EAMs embedded in silicon photonic integrated circuits, this EAM is shorter and has a quite small insertion loss. The EAM's large feature size may enable fabrication using 248 nm optical lithography, and the EAM is expected to function as a compact modulator, well-integrated with silicon photonic devices.

Optically controlled millimetre‐wave switch with stepped‐impedance lines

A photoconductive grounded coplanar waveguide (GCPW) millimetre-wave switch controlled by a single infrared light-emitting diode is presented. By converting a straight GCPW transmission line into an alternating stepped-impedance line structure, the proposed device shows an on-state insertion loss of <2.9 dB and an off-state isolation of more than 15 dB over a wide-frequency range of 12–30 GHz, with a particularly good radio-frequency performance in the K-band (18–27 GHz). The required optical power and electrical power of the switch are only 199 and 364 mW, respectively. This device also demonstrates an absorptive characteristic with a low reflection coefficient of <−13.5 dB within this frequency range for both the on and off states. In addition, by employing through-holes for illumination of a silicon superstrate, the proposed device can be fabricated with rapid and low-cost laser etching and can be easily integrated with other microwave and millimetre-wave circuits.

Single-Pole Single-Throw Switch for Substrate-Integrated Waveguide

A novel concept of a simple single-pole single-throw switch implementation for a substrate-integrated waveguide is presented in this letter. The switch design is an adaptation from the antenna theory where a resonant slot on a rectangular waveguide, inclined with respect to the line axis, realizes a series impedance load on the waveguide. This impedance can be designed to attenuate the signal flowing through the transmission line while minimizing radiation and can be activated by loading the slot with a diode. A prototype was fabricated to validate the proposed concept. The prototype was measured and it had an ON-state insertion loss of less than 1.3 dB, an OFF-state isolation of more than 10 dB, and a switchable bandwidth of 21% at 22 GHz.

Quasi-Lumped-Element Filter-Integrated Single-Pole Double-Throw Switch

In this paper, the capacitively coupled LC resonators with loaded p-i-n diodes are used to develop fixed-response filter-integrated single-pole double-throw (SPDT) switch. The filter-integrated on-state channel with reverse-biased p-i-n diodes can be designed and synthesized using the coupled-resonator filter theory, and the off-state channel with forward-biased p-i-n diodes exhibits high suppression. A 1-GHz filter-integrated SPDT switch with ripple bandwidth of 195 MHz is designed to demonstrate the proposed design concept. Measured results show that it has a low on-state insertion loss (IL) of 1.03 dB, a wide passband, high off-state suppression (OSS), high port-to-port isolation, and compact circuit size. Since both the properly misaligned resonant frequencies of LC resonators and weakly coupling between LC resonators also result in high suppression, a frequency-agile filter-integrated switchless SPDT switch without p-i-n diodes can be designed by using the varactor diodes to realize the corresponding capacitors. A frequency-agile filter-integrated switchless SPDT switch with constant 1-dB fractional bandwidth of 19.5% is also designed. Measured results show that its operating frequency can be tuned from 0.612 to 1.088 GHz with corresponding frequency tuning range of 58% and IL varying from 2.8 to 2.3 dB. Good return loss, high OSS, and port-to-port isolation can be also observed.

Single- and Dual-Band LTCC Filtering Switch With High Isolation Based on Coupling Control

This paper presents a novel method for designing single- and dual-band filtering switches based on coupling control. First, the ON- and OFF-state coupling matrices are analyzed to achieve bandpass responses and high isolation, respectively. Then, they are used to guide the low temperature cofired ceramic circuit realization. The ON- and OFF-states are enabled by controlling the PIN diodes in the filter feeding structures. In the ON-state, the circuit is equivalent to a bandpass filter without signals passing through the PIN diodes, which avoids additional loss introduced by the PIN diodes. For the OFF-state isolation, it is realized by controlling the coupling of the filtering circuit, which is different from that of conventional switches by turning off transistors or diodes to obtain isolation. Thus, isolation is considerably enhanced. For demonstration, a single-band filtering switch is implemented with a compact size of 0.050 λg × 0.048 λg × 0.023 λg . Furthermore, a dual-band one of the same dimension is realized with controllable passband frequencies and bandwidths in the ON-state as well as high isolation in OFF-state. The presented filtering switches feature compact size, low ON-state insertion loss, high OFF-state isolation, and high reliability, which are suitable for industrial applications.

RF MEMS switches for smart antennas

In this paper novel V-shaped and Z-shaped thermally actuated radio frequency (RF) MicroElectroMechanical Systems (MEMS) switches are designed and fabricated for the application of smart antennas. The switches are driven by a metal electrothermal actuator, which is able to generate large displacement and high contact force at lower temperatures. The MEMS switches utilizing the parallel beam actuator achieved 8 μm displacement. RF performances are improved by suspending the switching structures 25 μm above the substrate, thereby reducing the loss in the substrate. ON state insertion loss of −0.42 dB at 10 GHz, OFF state isolation of −40 dB at 10 GHz and return loss better than of −20 dB at 10 GHz for bidirectional Z-shaped thermally actuated RF MEMS switch are achieved on the low resistivity silicon substrate.

Theory and Design of Intrinsically Switched Multiplexers With Optimum Phase Linearity

This paper presents the theory, design, and implementation of a new class of component called an intrinsically switched multiplexer, which is comprised of a number of contiguous bandpass filter channels that can be independently switched on and off with very low architecture-related insertion loss and flat group delay across adjacent switched-on channels. Coupled-resonator filter topologies are identified that allow for optimum performance of contiguous bandpass channel filters through the crossover frequencies, and a new intrinsically switched coupling section that provides for low on-state insertion loss and high broadband off-state isolation is presented. In addition, it is shown that the channel filters can be combined in a scalable fashion with the use of lossy manifolds. A three-channel eight-state intrinsically switched multiplexer microstrip prototype was designed, built, and tested and gives 6.7 dB of passband insertion loss and 0.15-ns p-p group delay ripple over 72% of the passband.

A Novel Bidirectional Z-Shaped Thermally Actuated RF MEMS Switch for Multiple-Beam Antenna Array

In this paper RF MEMS switchis designed for dielectric-embedded electronically switched multiple-beam (DE-ESMB) antenna array. To achieve small stiffness without buckling, a novel bidirectional Z-shaped thermal actuator is used instead of V-shaped thermal actuator, which can generate large displacement and high contact force at low actuation voltage. With the actuation current from-0.6 A to 0.6 A, the electrothermal actuator can achieve a bidirectional motion in a dynamic range of-10.08 μm to 10.17 μm.RF performances are improved by suspending the structure 25 μm from the substrate using MetalMumps process. An ON state insertion loss of-0.14 dB at 10 GHz and an OFF state isolation of-67 dB at 10 GHz are achieved on low resistivity silicon substrate.

A low insertion loss GaAs pHEMT switch utilizing dual n+-doping AlAs etching stop layers design

Abstract A low insertion loss single-pole-single-throw (SPST) pseudomorphic high electron mobility transistor (pHEMT) switch utilizing the n + -type doping in AlAs etching stop layer was fabricated and investigated. This novel design reduces device sheet resistance resulting in an improvement of dc and rf power performance. In addition, the gate recess selectivity for GaAs/AlAs interface was not sacrificed after highly n + -type doping in AlAs etching stop layer. The pHEMT with n + -AlAs etching stop layer, also named Modified pHEMT (M-pHEMT), demonstrated a lower sheet resistance ( R sh ) of 65.9 Ω/γ, a higher maximum drain-to-source current ( I dmax ) of 317.8 mA/mm and a higher peak transconductance ( g m ) of 259.3 mS/mm which are superior to standard pHEMT performance with values of 71.9 Ω/γ, 290.3 mA/mm and 252.1 mS/mm, respectively. Due to a significant sheet resistance improvement from this novel epitaxial design, an SPST pHEMT switch was realized to manifest its industrial application potential. The results achieved an on-state insertion loss of 1.42 dB, an off-state isolation of 13.02 dB at 0.9 GHz, which were superior to traditional pHEMT switch under same condition of operation with values of 1.68 dB and 11.42 dB, respectively. It is proved that dual n + -doping AlAs etching stop layers scheme is beneficial for low loss microwave switches applications.

High-power monolithic AlGaN/GaN HEMT switch for X-band applications

The design, fabrication and test of X-band high-power monolithic SPDT switches in microstrip GaN technology are presented. Such switches have demonstrated state-of-the-art performance: they exhibit 1 dB on-state insertion loss and better than 37 dB isolation. Power-handling measurements have shown that no compression phenomenon occurs with an input power equal to 39.5 dBm at 10 GHz.

Microstrip lateral RF MEMS switch integrated with multistep CPW transition

A new type of microstrip lateral metal-contacting micro-electromechanical systems (MEMS) series switch using an enhanced transition-design technology is proposed and demonstrated. It uses a conductor-backed coplanar waveguide (CBCPW) connected to a microstrip back-to-back MEMS transmission line without any via holes or bonded wires. The RF measurements of this switch show an off-state isolation of 18 dB and an on-state insertion loss of less than 2 dB at 6–27 GHz. In addition, the simplicity of this fabrication process is achieved using deep reactive-ion etching (DRIE), micromachining technology, and silicon-on-insulator (SOI) substrate. © 2004 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 93–95, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20557