Showing papers on "Insertion loss published in 2005"

An electronically tunable microstrip bandpass filter using thin-film Barium-Strontium-Titanate (BST) varactors

Abstract: A tunable third-order combline bandpass filter using thin-film barium-strontium-titanate varactors and fabricated on a sapphire substrate is reported. Application of 0-200-V bias varied the center frequency of the filter from 2.44 to 2.88 GHz (16% tuning) while achieving a 1-dB bandwidth of 400 MHz. The insertion loss varied from 5.1 dB at zero bias to 3.3 dB at full bias, while the return loss exceeded 13 dB over the range. The third-order intercept of the filter was found to be 41 dBm.

A differential 4-bit 6.5-10-GHz RF MEMS tunable filter

Abstract: This paper presents a state-of-the-art RF microelectromechanical systems wide-band miniature tunable filter designed for 6.5-10-GHz frequency range. The differential filter, fabricated on a glass substrate using digital capacitor banks and microstrip lines, results in a tuning range of 44% with very fine resolution, and return loss better than 16 dB for the whole tuning range. The relative bandwidth of the filter is 5.1 /spl plusmn/ 0.4% over the tuning range and the size of the filter is 5 mm /spl times/ 4 mm. The insertion loss is 4.1 and 5.6 dB at 9.8 and 6.5 GHz, respectively, for a 1-k/spl Omega//sq fabricated bias line. The simulations show that, for a bias line with 10-k/spl Omega//sq resistance or more, the insertion loss improves to 3 dB at 9.8 GHz and 4 dB at 6.5 GHz. The measured IIP/sub 3/ level is > 45 dBm for /spl Delta/f > 500 kHz, and the filter can handle 250 mW of RF power for hot and cold switching.

An ultrawideband bandpass filter using broadside-coupled microstrip-coplanar waveguide structure

Abstract: This paper presented an ultra-wideband (UWB) bandpass filter using broadside-coupled microstrip-coplanar waveguide structure. The filter consists of a microstrip line coupled to a coplanar waveguide (CPW) that was fabricated on the ground of the microstrip line. The proposed filter has been simulated, fabricated and measured for UWB system. The measured results demonstrated the UWB properties from 3.0 GHz to 10.63 GHz (-10 dB bandwidth) and the potential to be wider. A threesection filter shown insertion loss at central frequency is about 0.32 dB and very flat over the whole band. The group delay, which is important to an impulse radio UWB system, is about 0.42 ns over the most central band and less than 0.95 ns over the whole band. The filter also exhibited a good performance outside the band, both at low frequency end (to meet FCC limit) and high frequency end higher than 18 GHz with insertion loss larger than 30 dB.

A 12-18-GHz three-pole RF MEMS tunable filter

Abstract: This paper presents a state-of-the-art RF microelectromechanical systems (MEMS) wide-band tunable filter designed for the 12-18-GHz frequency range The coplanar-waveguide filter, fabricated on a glass substrate using loaded resonators with RF MEMS capacitive switches, results in a tuning range of 40% with very fine resolution, and return loss better than 10 dB for the whole tuning range The relative bandwidth of the filter is 57/spl plusmn/04% over the tuning range and the size of the filter is 8 mm/spl times/4 mm The insertion loss is 55 and 82 dB at 178 and 122 GHz, respectively, for a 2-k/spl Omega//sq bias line The loss improves to 45 and 68 dB at 178 and 122 GHz, respectively, if the bias line resistance is increased to 20 k/spl Omega//sq The measured IIP/sub 3/ level is >37 dBm for /spl Delta/f>200 kHz To our knowledge, this is the widest band planar tunable filter to date

Compact super-wide bandpass substrate integrated waveguide (SIW) filters

Abstract: It is known that the substrate integrated waveguide (SIW) features high-pass characteristics of the conventional waveguide, and a periodic structure (PS) generally presents bandstop characteristics. Therefore, a super-wide-band bandpass characteristic should be realized by combining some sort of PS into the SIW. In this paper, three types of compact SIW-PS wide-band bandpass filters are proposed and investigated with simulation and experiment. Performances of a super-wide bandpass, for instance, 8.5-16.5 GHz in this case study, with low insertion loss and sharp out-of-band characteristics are observed from both simulated and measured results.

Wideband and low dispersion slow light by chirped photonic crystal coupled waveguide

Abstract: Previously, we discussed an optical delay device consisting of a directional coupler of two different photonic crystal (PC) waveguides. It generates wideband and low dispersion slow light. However, it is easily degraded by a large reflection loss for a small imperfection of the coupling condition. In this paper, we propose and theoretically discuss a PC coupled waveguide, which allows more robust slow light with lower loss. For this device, unique photonic bands with a zero or negative group velocity at the inflection point can be designed by the structural tuning. Finite difference time domain simulation demonstrates the stopping and/or back and forth motion of an ultrashort optical pulse in the device combined with the chirped structure. For a signal bandwidth of 40 GHz, the average group index of the slow light will be 450, which gives a 1 ns delay for a device length of 670 μm. The theoretical total insertion loss at the device and input/output structures is as low as 0.11 dB.

A broadband series power divider using zero-degree metamaterial phase-shifting lines

Abstract: A metamaterial 1:4 series power divider that provides equal power split to all four output ports over a large bandwidth is presented, which can be extended to an arbitrary number of output ports. The divider comprises four nonradiating metamaterial lines in series, incurring a zero insertion phase over a large bandwidth, while simultaneously maintaining a compact length of /spl lambda//sub 0//8. Compared to a series power divider employing conventional one-wavelength long meandered transmission lines to provide in-phase signals at the output ports, the metamaterial divider provides a 165% increase in the input return-loss bandwidth and a 155% and 154% increase in the through-power bandwidth to ports 3 and 4, respectively. In addition, the metamaterial divider is significantly more compact, occupying only 2.6% of the area that the transmission line divider occupies. The metamaterial and transmission line dividers exhibit comparable insertion losses.

Design of sharp-rejection and low-loss wide-band planar filters using signal-interference techniques

Abstract: A new class of sharp-rejection, low insertion-loss wide-band planar filters is presented in this letter. The proposed filter topology uses transversal signal-interference filtering sections made up of two transmission-line segments connected in parallel. Thus, under signal-interaction principles, the filtering action comes about through the generation of multiple out-of-band power transmission zeros and constructive in-passband signal combinations. Design equations and guidelines to adjust both the bandwidth and the out-of-band performance of the filtering response through the design parameters of the transversal section are also provided. Furthermore, the theoretical results are validated with the manufacture and characterization of an ultra-wideband microstrip filter prototype at 5 GHz.

Compact and wideband microstrip bandstop filter

Abstract: A novel one-section bandstop filter (BSF), which possesses the characteristics of compact size, wide bandwidth, and low insertion loss is proposed and fabricated. This bandstop filter was constructed by using single quarter-wavelength resonator with one section of anti-coupled lines with short circuits at one end. The attenuation-pole characteristics of this type of bandstop filters are investigated through TEM transmission-line model. Design procedures are clearly presented. The 3-dB bandwidth of the first stopband and insertion loss of the first passband of this BSF is from 2.3 GHz to 9.5 GHz and below 0.3 dB, respectively. There is good agreement between the simulated and experimental results.

Theory and experiment of novel frequency selective surface based on substrate integrated waveguide technology

Abstract: A novel frequency selective surface (FSS) based on substrate integrated waveguide (SIW) technology is investigated with simulation and experiment. The periodic unit is made of a SIW cavity with slots on the top and bottom surfaces, and the whole FSS is fabricated on a microwave substrate with standard PCB process. The high-Q property of SIW cavities greatly improved the frequency selectivity of the FSS, which is significant for the application in antenna cover or object stealth etc. The finite difference frequency domain (FDFD) method is adopted to simulate the transmission and reflection characteristics of the proposed FSS, and the simulated results are in good agreement with the experiment data. Both simulated and experiment results show that the FSS proposed in this paper takes the advantages of low passband insertion loss, good frequency selectivity, and insensitive to the incident angle and polarization etc. Besides, the FSS can be easily fabricated using normal PCB process with low cost.

Analysis and design of current probe transition from grounded coplanar to substrate integrated rectangular waveguides

Abstract: The transition between a grounded coplanar waveguide (GCPW) and a substrate integrated rectangular waveguide (SIRW) is investigated in this paper. The proposed scheme makes use of a current probe to transfer power between the two dissimilar transmission lines. A computer-aided-design-oriented analytical model is developed in order to optimize the geometrical dimensions of the transition. By using the GCPW instead of the microstrip line to interface the SIRW, substrate thickness can be increased without incurring a penalty due to transmission loss. Therefore, it is possible to achieve higher Q components. Experiments at 28 GHz show that an effective bandwidth of 10% can easily be obtained. The insertion loss is less than 0.73 dB over the bandwidth of interest.

A novel CPW‐fed ultra‐wideband antenna design

Abstract: A novel ultra-wideband (UWB) antenna fed by coplanar waveguide (CPW) is designed, fabricated, and measured for UWB communications. It is designed to work on a substrate TMM4 of thickness 0.762 mm and relative permittivity 4.5, and to operate from 3.1 to 8.3 GHz. Details of the proposed antenna design and the measured results are presented and discussed. Measured insertion loss is almost constant across the frequency band and the group-delay variation is less than 1 ns, thus indicating that the proposed antenna is a good candidate for UWB applications. © 2005 Wiley Periodicals, Inc. Microwave Opt Technol Lett 44: 393–396, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.20646

Linear tunable phase shifter using a left-handed transmission line

Abstract: We demonstrate a compact, linear, and low loss variation hybrid phase shifter using a left-handed (LH) transmission line. For frequencies from 4.3 to 5.6 GHz, this phase shifter gives a nearly linear phase variation with voltage, with a maximum deviation of /spl plusmn/7.5/spl deg/. Within this frequency range, the maximum insertion loss is 3.6 dB, and the minimum insertion loss is 1.8 dB over a continuously adjustable phase range of more than 125/spl deg/, while minimum return loss is only 10.2 dB. Furthermore, this phase shifter requires only one control line, and it consumes almost no power.

Highly integrated millimeter-wave passive components using 3-D LTCC system-on-package (SOP) technology

Abstract: In this paper, we demonstrate the development of advanced three-dimensional (3-D) low-temperature co-fired ceramic (LTCC) system-on-package (SOP) passive components for compact low-cost millimeter-wave wireless front-end modules. Numerous miniaturized easy-to-design passive circuits that can be used as critical building blocks for millimeter-wave SOP modules have hereby been realized with high-performance and high-integration potential. One miniaturized slotted-patch resonator has been designed by the optimal use of vertical coupling mechanism and transverse cuts and has been utilized to realize compact duplexers (39.8/59 GHz) and three- and five-pole bandpass filters by the novel 3-D (vertical and parallel) deployment of single-mode patch resonators. Measured results agree very well with the simulated data. One multiplexing filter, called the directional channel-separation filter, that can also be used in mixer applications shows insertion loss of <3 dB over the bandpass frequency band and a rejection /spl sim/25 dB at around 38.5 GHz over the band-rejection section. LTCC fabrication limitations have been overcome by using vertical coupling mechanisms to satisfy millimeter-wave design requirements. Lastly, a double-fed cross-shaped microstrip antenna has been designed for the purpose of doubling the data throughput by means of a dual-polarized wireless channel, covering the band between 59-64 GHz. This antenna can be easily integrated into a wireless millimeter-wave link system.

Low-loss LTCC cavity filters using system-on-package technology at 60 GHz

Abstract: In this paper, three-dimensional (3-D) integrated cavity resonators and filters consisting of via walls are demonstrated as a system-on-package compact solution for RF front-end modules at 60 GHz using low-temperature cofired ceramic (LTCC) technology. Slot excitation with a /spl lambda/g/4 open stub has been applied and evaluated in terms of experimental performance and fabrication accuracy and simplicity. The strongly coupled cavity resonator provides an insertion loss 20.6 dB over the passband (/spl sim/0.89 GHz), and a 3-dB bandwidth of approximately 1.5% (/spl sim/0.89 GHz), as well as a simple fabrication of the feeding structure (since it does not require to drill vias to implement the feeding structure). The design has been utilized to develop a 3-D low-loss three-pole bandpass filter for 60-GHz wireless local area network narrow-band (/spl sim/1 GHz) applications. This is the first demonstration entirely authenticated by measurement data for 60-GHz 3-D LTCC cavity filters. This filter exhibits an insertion loss of 2.14 dB at the center frequency of 58.7 GHz, a rejection >16.4 dB over the passband, and a 3-dB bandwidth approximately 1.38% (/spl sim/0.9 GHz).

The state-of-the-art of silicon-on-sapphire CMOS RF switches

Abstract: Silicon-on-Sapphire (SOS) CMOS FETs have many properties which are desirable for RF switch applications. By being manufactured on an insulating sapphire substrate, the bulk parasitic capacitances typical of CMOS FETs are eliminated. The SOS FET has a very low Ron-Coff product, allowing for low insertion loss and high isolation in high frequency applications. Despite the low breakdown voltage intrinsic to Si, SOS FETs can be stacked in series to withstand high voltages when biased in subthreshold. This work studies the tradeoffs of SOS RF switch design and compares SOS against other technologies such as GaAs and Si-based SOI. Also presented is a high power SP6T switch with insertion loss of 0.6 dB at 2 GHz and isolation of 40 dB at 2 GHz. The presented switch has the highest linearity reported to date of any SP6T switch with a P1dB of 20 W and OIP3 of <+70 dBm.

A low-voltage and low-power RF MEMS series and shunt switches actuated by combination of electromagnetic and electrostatic forces

Abstract: This paper reports new RF microelectromechanical systems (MEMS) switches actuated by the combination of electromagnetic and electrostatic forces for low-voltage and low-power operation. The proposed RF MEMS switches have utilized the proper combination of two actuation mechanisms: taking advantage of the large actuation force from electromagnetic actuation for initial movement and the low-power feature from electrostatic actuation for holding the actuator position. Both series- and shunt-type switches have been implemented using the proposed actuation mechanism. From the fabricated switches, feasibility of operation has been successfully demonstrated. The fabricated switches can be operated within several hundred microseconds. In the series-type switch, the isolation has been measured as -34dB and insertion loss as -0.37dB at 20 GHz. In the shunt type switch, the isolation is -20.7dB and insertion loss is -0.85dB at 19.5 GHz. The proposed RF MEMS switches are mechanically robust and the combination of electromagnetic and electrostatic actuations makes it possible to achieve excellent switching characteristics at low power and low voltage below 5 V.

Band reject filters

Abstract: Acoustic resonators such as surface acoustic wave (SAW) devices and thin film bulk acoustic resonators (FBAR) can be configured to produce a band reject filter. Such a filter overcomes the insertion loss and power handling limitations of conventional band pass configurations and as such can be used in power amplifier and duplexer applications.

Design, fabrication and RF performances of two different types of piezoelectrically actuated Ohmic MEMS switches

Abstract: In this paper, we have proposed, fabricated and characterized piezoelectrically actuated RF MEMS (radio-frequency micro-electro-mechanical system) switches. They have been designed to operate at a low operation voltage for advanced mobile/wireless handset applications. The proposed switches are largely composed of piezoelectric cantilever actuators with an Au contact electrode and CPW (coplanar wave) transmission lines suspended over the substrate. Two different types of RF MEMS switches have been suggested to find the better geometry. One has the structure of one single piezoelectric cantilever and a contact electrode attached to its edge with three hinges (type-A), and the other contains four piezoelectric cantilevers that are symmetrically combined through each hinge to support a centered contact electrode (type-B). The two different fabricated (type-A and type-B) RF MEMS switches have insertion losses of −0.22 and −0.23 dB at an operation voltage of 2.5 V and a frequency of 2 GHz, respectively. Although the difference in insertion loss is trivial, there exist different dependences of insertion loss on applied voltage between them. The insertion losses of type-A switches are changed with varying operation voltage because the touching area between the contact electrode and the signal transmission lines is variable. Meanwhile, the type-B switches show nearly constant insertion losses regardless of operation voltage. The type-A and type-B switches have isolation values of −40.8 and −42.5 dB at a frequency of 2 GHz, respectively.

Control of enhanced THz transmission through metallic hole arrays using nematic liquid crystal.

Abstract: We demonstrate frequency tuning of enhanced THz radiation transmitted through a two-dimensional metallic hole array (2D-MHA) by controlling the index of refraction of the medium filling the holes and adjacent to the 2D-MHA on one side. The medium is a nematic liquid crystal (NLC) and its index of refraction is varied using magnetically controlled birefringence of the NLC. With the NLC, the peak transmission frequency of the 2D-MHA shift to the red by 0.112 THz and can be tuned from 0.193 to 0.188 THz. The peak transmittance is as high as 70% or an enhancement of 2.42 times, considering the porosity of the 2D-MHA. As a tunable THz filter, this device exhibits a continuous tuning range of 4.7 GHz, a low insertion loss of 2.35 to 1.55 dB and a quality factor of ~4–5.

Corrugated waveguide and directional coupler for CW 250-GHz gyrotron DNP experiments

Abstract: A 250-GHz corrugated transmission line with a directional coupler for forward and backward power monitoring has been constructed and tested for use with a 25-W continuous-wave gyrotron for dynamic nuclear polarization (DNP) experiments. The main corrugated line (22-mm internal diameter, 2.4-m long) connects the gyrotron output to the DNP probe input. The directional coupler, inserted approximately midway, is a four-port crossed waveguide beamsplitter design. Two beamsplitters, a quartz plate and ten-wire array, were tested with output coupling of 2.5% (-16dB) at 250.6 GHz and 1.6% (-18dB), respectively. A pair of mirrors in the DNP probe transferred the gyrotron beam from the 22-mm waveguide to an 8-mm helically corrugated waveguide for transmission through the final 0.58-m distance inside the NMR magnet to the sample. The transmission-line components were all cold tested with a 248/spl plusmn/4-GHz radiometer. A total insertion loss of 0.8 dB was achieved for HE/sub 11/-mode propagation from the gyrotron to the sample with only 1% insertion loss for the 22-mm-diameter waveguide. A clean Gaussian gyrotron beam at the waveguide output and reliable forward power monitoring were achieved for many hours of continuous operation.

Compact microstrip low-pass filter with sharp rejection

Abstract: This letter presents a compact multisection sharp-rejection microstrip low-pass filter. Each section consists of a microstrip line section and an interdigital capacitor. The analysis for optimizing the attenuation poles by adjusting the finger number, and the width and length of the microstrip line section, is presented. The cascaded four-section low-pass filter has a return loss of better than 17 dB and an insertion loss of less than 0.7 dB from DC to 1.6 GHz. The rejection is better than 20 dB from 2.1 to 7.5 GHz.

Wavelength demultiplexer consisting of Photonic crystal superprism and superlens

Abstract: We propose a novel compact wavelength demultiplexer, for which two functions arising from the anomalous dispersion characteristics of photonic crystals are combined. One is the superprism that exhibits large angular dispersion and expansion of light beam. The other is the superlens used for the focusing of the expanded light beam. Theoretically, a high resolution of 0.4 nm will be realized in the 1.55 μm wavelength range with device areas of 0.2 and 2.0 mm2, respectively, for available bandwidths of 3 and 35 nm. Also, a low insertion loss of less than 1 dB is expected by the optimization of input and output ends of the photonic crystals. The demultiplexing function is clearly demonstrated in finite-difference time-domain simulation.

Behavior of BAW devices at high power levels

Abstract: Bulk acoustic wave (BAW) and FBAR technologies offer key advantages for transmit filters which are used between the power amplifier and antenna in cell phone applications. The classical challenge for Tx filters in duplexers is to achieve low insertion loss, high return loss, high Rx - Tx isolation and good wideband performance at the same time. The trade-offs between those parameters can be modeled in a straightforward approach as will be briefly described. The main section of this paper discusses 2nd order effects which become relevant at high power levels. The energy loss in each individual BAW resonator generates a shift and spread of resonance frequencies in the filter elements by self-heating effects. These effects can cause unexpected performance issues and may even lead to thermal instability. A concept for modeling of self-heating effects is presented in detail. The role of self-heating with regard to power-handling capability of a filter will be pointed out. As a consequence of extreme energy density at high power levels a certain degree of non-linear effects can be observed in BAW/FBAR filters. The origin of these effects will be discussed as well as a modeling strategy. This is in particular important for emerging W-CDMA applications of BAW and FBAR filters.

Complementary split ring resonators for microstrip diplexer design

Abstract: A new topology for the design of microstrip microwave diplexers, based on the use of quasi-lumped resonators, is presented. Specifically, the receiver (Rx) and transmitter (Tx) filters of the diplexer are implemented by etching complementary split ring resonators (CSRRs) in the ground plane as well as series capacitive gaps and shunt inductive strips in the upper metal level. By this means, narrowband microwave diplexers with transmission zeros can be synthesised, which allow for the improvement of Rx/Tx isolation. A prototype device operative in the 2.4-3.0 GHz frequency band is presented. Measured insertion losses are lower than 2 dB while the isolation between Rx/Tx channels is in the vicinity of 40 dB. Diplexer dimensions (29.8/spl times/16.3 mm), which are small on account of the semi-lumped resonators employed, and performance point to the practical application of these structures in communication transceiver front-ends.

High-order tunable filters based on a chain of coupled crystalline whispering gallery-mode resonators

Abstract: We demonstrate experimentally a tunable third-order optical filter fabricated from the three voltage-controlled lithium niobate whispering gallery-mode resonators. The filter operates at 1550 nm with 30-MHz bandwidth and can be electrooptically tuned by 12 GHz in the linear regime with approximately 80-MHz/V tuning rate. With this filter, we have demonstrated 6-dB fiber-to-fiber insertion loss and 30-ns tuning speed, limited by the resonator buildup time.

Piezoelectrically actuated RF MEMS DC contact switches with low voltage operation

Abstract: In this paper, fully integrated radio frequency (RF) microelectromechanical system (MEMS) switches with piezoelectric actuation have been proposed, designed, fabricated, and characterized. At a very low operation voltage of 2.5V, reliable and reproducible operation of the fabricated switch was obtained. The proposed RF MEMS switch is comprised of a piezoelectric cantilever actuator with a floated contact electrode and isolated CPW transmission line suspended above the silicon substrate. The measured insertion loss and isolation of the fabricated piezoelectric switch are -0.22 dB and -42dB at a frequency of 2GHz, respectively.

A miniaturized Wilkinson power divider with CMOS active inductors

Abstract: A miniaturized Wilkinson power divider implemented in a standard 0.18-/spl mu/m CMOS process is presented in this letter. By using active inductors for the circuit implementation, a significant area reduction can be achieved due to the absence of distributed components and spiral inductors. The power divider is designed at a center frequency of 4.5GHz for equal power dividing with all ports matched to 50/spl Omega/. Drawing a dc current of 9.3mA from a 1.8-V supply voltage, the fabricated circuit exhibits an insertion loss less than 0.16dB and a return loss better than 30dB at the center frequency while maintaining good isolation between the output ports. The active area of the miniaturized Wilkinson power divider is 150/spl times/100/spl mu/m/sup 2/, which is suitable for system integration in monolithic microwave integrated circuit (MMIC) applications.

High-speed silicon electrooptic Modulator design

Abstract: An electrically driven Mach-Zehnder waveguide modulator based on high-index contrast silicon split-ridge waveguide technology and electronic carrier injection is proposed. The excellent optical and carrier confinement possible in high-index contrast waveguide devices, together with good thermal heat sinking and forward biased operation, enables high-speed modulation with small signal modulation bandwidths beyond 20 GHz, a V/sub /spl pi// times length figure of merit of V/sub /spl pi//L=0.5 V/spl middot/cm and an insertion loss of about 4 dB. The modulator can be fabricated in a complementary metal-oxide-semiconductor compatible way.