Reduce Insertion Loss Research Articles

Adaptive Cancellation of Digital Power Amplifier Receive Band Noise for FDD Transceivers

In frequency division duplex systems, spurious emission from transmitter (TX) can fall into receive band and lead to significant receiver desensitization. In this paper, a DSP-based solution that relies on a linear auxiliary receiver to cancel receive band noise (RxBN) from the received signal is demonstrated. This technique allows reduction of duplexer rejection requirements in the receiver band, and associated reduction of insertion loss in the TX band, thus resulting in high-power amplifier (PA) efficiency and small duplexer footprint. The PA architectures that inherently have high RxBN (such as envelope tracking and the digitally modulated PAs) can substantially benefit from this technique. Experimental results based on off-the-shelf system implementation are demonstrated using a digital PA, and more than 22 dB cancellation is achieved to reduce RxBN below thermal noise floor at 836 MHz with 45 MHz duplex spacing.

Novel spoof surface plasmon polaritons on a planar metallic strip with periodic semi-elliptical grooves at microwave frequency

ABSTRACTIt is well known that traditional microstrip (MS) transmission lines suffer from high transmission losses at microwave and millimeter wave frequencies. To solve the issue, a novel periodic subwavelength structure is proposed in this work with semi-elliptical grooves (SEGs) on a lateral edge of MS line, for the propagation of spoof surface plasmon polaritons (SSPPs) in the microwave regime. Dispersion relations are analyzed by a numerical method using ANSYS’s HFSS (High-Frequency Structure Simulator), and ability to operate efficiently in primary mode is demonstrated. A comparison with other structures is also accomplished and found that more strong resonant modes are created by the coupling between upper metal strip with textured SEGs and the lower ground layer which are confined near the surface of this grating structure. It has been observed that the cutoff frequency (fc) and the level of field confinement depend on the geometric parameters, and SEG-based SSPPs efficiently minimize the asymptotic frequency by 65% and 12% as compared to MS and Vee-groove structures, respectively. We further investigate a planar and highly efficient, low-pass plasmonic filter with 3 dB cutoff frequency of 11.4 GHz and significantly reduced insertion loss (>−1.9 dB) in the passband. A prototype is fabricated for validation by standard PCB manufacturing process; good agreement between experimental and simulation results confirms the excellent performance of this compact filter in the entire passband with smaller transmission losses. Such a plasmonic metamaterial structure presents a unique and highly unexplored geometry which strongly supports confined SSPPs, therefore, can play a significant role in advanced integrated plasmonics circuitry and applications.

Application mapping in hybrid photonic networks-on-chip for reducing insertion loss

In this paper, the influence of the mapping algorithm on the physical layer parameters and photonic network-on-chip performance is demonstrated. Four mapping algorithms, namely hop count, congestio...

Real-time waveform modulator based on dispersion engineering of magnetic surface plasmons

With the aim to further reduce insertion loss, we propose the design of a real-time waveform modulator by engineering the dispersion of magnetic surface plasmons (MSPs). The magnetic fields of MSPs are strongly localized, which is different from conventional electric surface plasmons (ESPs). Since there are no magnetic media in the design, the transmission loss of MSPs resulting from dielectric loss is lower than that of ESPs. Therefore, a waveform modulator with lower insertion loss can be realized. As an example, we demonstrate a real-time waveform modulator operating in the X band. Both the simulation and experiment prove that the waveform modulator is broadband and high-efficiency. The design method can also be applied to the design of a true-time delayer, a real-time Fourier transformer, a true-time compressor, and so on.

A compact UWB‐BPF based on microstrip‐to‐CPW transition with multiple transmission zeros

AbstractA hybrid microstrip‐to‐coplanar waveguide (CPW) based broadside coupled ultra‐wideband (UWB) bandpass filter (BPF) of compact nature with multiple transmission zeros (TZ) is proposed. The CPW in ground consists of a short circuited multiple mode resonator (MMR), which is in conjugation with two microstrip lines on the top, arranged in back‐to‐back manner. Initially, the impedance ratio of the MMR is adjusted to place its resonant modes quasi‐equally within the UWB passband and later the dimensions of microstrip lines are optimized to enhance the broadside coupling. The setup generates a passband with reduced insertion loss, small group delay and multiple TZ. The presence of TZs provide sharp roll‐offs at either passband edges and a wide stopband. The experimental BPF is fabricated and its measured data validated against simulation results. The proposed structure measures 14.6 × 9.6 mm2.

Multilayer optical interconnects design: switching components and insertion loss reduction approach

Abstract The next generation of chip multi-processors point to the integration of thousands of processing cores, demanding high- performance interconnects, and growing the interest in optically interconnected networks. In this article we report on an interlayer silicon-based switch design that switches two channels simultaneously from an input waveguide into one of the two output ports. The introduced interlayer switch allows to design interconnects with previously unattainable functionality, higher performance and robustness, and smaller footprints with low insertion loss (< 1 dB), and high extinction ratio (> 18 dB). Interlayer switching combined with wavelength-routed and circuit-switched networks yield a low latency and low- loss interconnect architecture. Quantitative comparison between the proposed interconnect architecture and other reported structures in terms of loss, number of wavelengths and microring resonators reveals the proficiency of our design. For a 64-core interconnect implemented in 4 layers, the proposed architecture indicates an average loss reduction up to 42% and 43% with respect to single-layer lambda-router and GWOR.

Reduction of Passband Insertion Loss for a Dual Band Bandstop Filter

Reduction of Passband Insertion Loss for a Dual Band Bandstop Filter

Frame structure for thin-film piezoelectric-on-silicon resonator to greatly enhance quality factor and suppress spurious modes

Thin-film piezoelectric-on-silicon (TPoS) bulk acoustic wave resonator provides an attractive vision of system-on-chip integrated circuits by micro/nano-engineering the timing reference. However, its quality factor (Q) at high frequency is a great challenge due to the mechanical loss. Herein, a novel suspended frame structure on tethers was proposed to significantly enhance the Q and suppress spurious modes of TPoS resonator working in the 30.4 MHz fundamental mode. Compared with the pristine one, the measured Q of fabricated resonator with frame structure showed a maximum 136-fold enhancement. The systematical investigation by both finite-element-analysis (FEA) simulation and experimental comparison revealed that the existing of frame structure effectively decreases the effective coupling coefficient (k2eff) of resonator and further results in the suppression of spurious modes and the enhancement of Q. As the width of frame structure increases, the k2eff maintains a consistent value of 0.15% while the anchor loss significantly reduced, which results in the reduction of insertion loss (IL) and the enhancement of Q.

Design and Performance Analysis of Hairpin Bandpass Filter for Satellite Applications

In this paper, a hairpin bandpass filter using coupled lines is designed for satellite applications. Initially, a conventional microstrip parallel coupled line filter is modified as hairpin based folded coupled line filter that works in S-band between 2-4GHz. The proposed filter is designed for the seventh order coupled line and its filter characteristics are analyzed. The idea of folded coupled lines are used for designing the ninth order folded coupled line filter which operates in 2.8GHz and the S-parameter results of filter are also discussed. The proposed seventh and ninth order filter has reduced insertion loss and high performance.

Highly Sensitive FPW-Based Microsystem for Rapid Detection of Tetrahydrocannabinol in Human Urine.

This paper presents a highly sensitive flexural plate-wave (FPW)-based microsystem for rapid detection of tetrahydrocannabinol (THC) in human urine. First, a circular-type interdigital transducer (IDT) was integrated with a circular-type silicon-grooved reflective grating structure (RGS) to reduce insertion loss. Then, with lower insertion loss (−38.758 dB), the FPW device was used to develop a novel THC biosensor, and the results reveal that this FPW-THC biosensor has low detection limit (1.5625 ng/mL) and high mass-sensitivity (126.67 cm2/g). Finally, this biosensor was integrated with field-programmable gate array (FPGA) board and discrete components for prototyping a FPW readout system, whose maximum error was 12.378 kHz to ensure that the linearity of detection up to R-square is equal to 0.9992.

A compact triple-band microwave filter using symmetrically placed stub-loaded open-loop resonators

ABSTRACTIn this paper, symmetrically placed stub-loaded open-loop resonators with magnetic coupling are used to design compact triple-band band pass filter (BPF) with improved insertion loss at passbands. Three bands of the proposed triple-band stub-loaded open-loop resonator filter are achieved by tuning length and position of open shunt stub which is connected with open-loop resonators. A lossless transmission line model is used to calculate the resonator properties. Theoretical design procedures are verified with an example of triple-band BPF design. Three passbands at 2.85, 5.9 and 8.15 GHz are achieved with reduced insertion loss. The insertion loss measured at first, second and third passbands are 0.47, 0.77 and 1.41 dB, respectively. First passband 2.76–2.9 GHz is used for the airport surveillance radar system and weather monitoring system. Second frequency band 5.82–6.16 GHz is used for the intelligent transportation system and third band 8.1–8.7 GHz is useful for satellite communication.

Efficient Integrated Graphene Photonics in the Visible and Near‐IR

AbstractGraphene photonics has emerged as a promising platform for providing desirable optical functionality. However, graphene's monolayer‐scale thickness fundamentally restricts the available light matter interaction, posing a critical design challenge for integrated devices, particularly in wavelength regimes where graphene plasmonics is untenable. While several plasmonic designs have been proposed to enhance graphene light interaction in these regimes, they suffer from substantial insertion loss due to metal absorption. Here we report a non‐resonant metamaterial‐based waveguide platform to overcome the design bottleneck associated with graphene device. Such metamaterial structure enables low insertion loss even though metal is being utilized. By examining waveguide dispersion characteristics via closed‐form analysis, it is demonstrated that the metamaterial approach can provide optimized optical field that overlaps with the graphene monolayer. This enables graphene‐based integrated components with superior optical performance. Specifically, the metamaterial‐assisted graphene modulator can provide 5‐fold improvement in extinction ratio compared to Si nanowire, while reducing insertion loss by one order magnitude compared to plasmonic structures. Such a waveguide configuration thus allows one to maximize the optical potential that graphene holds in the telecom and visible regimes.

High quality silicon-based substrates for microwave and millimeter wave passive circuits

Porous silicon substrate is very promising for next generation wireless communication requiring the avoidance of high-frequency losses originating from the bulk silicon. In this work, new variants of porous silicon (PSi) substrates have been introduced. Through an experimental RF performance, the proposed PSi substrates have been compared with different silicon-based substrates, namely, standard silicon (Std), trap-rich (TR) and high resistivity (HR). All of the mentioned substrates have been fabricated where identical samples of CPW lines have been integrated on. The new PSi substrates have shown successful reduction in the substrate's effective relative permittivity to values as low as 3.7 and great increase in the substrate's effective resistivity to values higher than 7kΩcm. As a concept proof, a mm-wave bandpass filter (MBPF) centred at 27GHz has been integrated on the investigated substrates. Compared with the conventional MBPF implemented on standard silicon-based substrates, the measured S-parameters of the PSi-based MBPF have shown high filtering performance, such as a reduction in insertion loss and an enhancement of the filter selectivity, with the joy of having the same filter performance by varying the temperature. Therefore, the efficiency of the proposed PSi substrates has been well highlighted.

Loss-aware routing algorithm for photonic networks on chip

Photonic network on chip was introduced as an efficient communication platform to overcome the existing challenges in traditional networks on chip. Optical networks provide high bandwidth and low power dissipation infrastructure. Insertion loss is one of the important parameters in photonic networks on chip. In this study, we propose a solution in routing algorithm level in order to reduce insertion loss in photonic network on chip, by passing packets through paths with lower number of optical elements. Simulation results reveal that a novel approach in the routing level decreases insertion loss as much as possible, energy consumption and optical power budget. Our proposed routing has 29.05% less insertion loss under all2all traffic pattern for blocking torus topology, and it has about 12.37% less insertion loss for TorusNX topology in comparison with primary dimension-ordered routing. Proposed routing algorithm increases both the network bandwidth and scalability.

High extinction ratio D-shaped fiber polarizers coated by a double graphene/PMMA stack.

We demonstrate theoretically and experimentally a high extinction ratio and compact size TE-pass polarizer made by a D-shaped fiber coated with a double graphene/PMMA stack. The light propagating in the core of the fiber can be efficiently coupled into the graphene sheet thanks to the giant enhancement of the modal evanescent field associated with the high refractive index graphene/PMMA cladding. The strong interaction between the light and graphene produces a large attenuation difference between modes with orthogonal polarizations, resulting in an improved extinction ratio and a reduced insertion loss due to the device compactness. A double graphene/PMMA stack coated polarizer with an extinction ratio of up to 36 dB and an insertion loss of 5 dB has been achieved when the device length is only 2.5 mm. The double graphene/PMMA stack has proved to be significantly better than single graphene/PMMA stack and bilayer graphene/PMMA structures, providing a polarizer with maximum extinction ratio of 44 dB for a length of 4 mm. The achieved results indicate that the proposed high extinction ratio polarizer is a promising candidate for novel in-fiber graphene-based devices.

Microwave Bandpass Filters Tuned by the Magnetization of Ferrite Substrates

C-band (around 5 GHz) microwave bandpass filters fabricated on yttrium-iron-garnet (YIG) and Al-doped-YIG ferrite substrates are tuned by an external magnetic field of 0 to 720 Oe. The filters on Al-doped YIG with lower saturation magnetization exhibit lower tuning ranges and sensitivities but reduced insertion losses and expanded bandwidths. The tunabilities of the filters are related to their partial or full magnetization states. Full magnetization states have three regimes: low field, resonance, and high field. The resonance regime cannot be used for bandpass filters. The detailed tuning mechanism is analyzed based on the dynamic magnetization states of magnetic materials. The results will provide a framework for the design of magnetically tunable bandpass filters.

Tunable Terahertz Metamaterials Employing Layered 2-D Materials Beyond Graphene

In this study, we extend recent investigations on graphene/metal hybrid tunable terahertz metamaterials to other two-dimensional (2-D) materials beyond graphene. For the first time, use of a nongraphitic 2-D material, molybdenum disulfide (MoS2), is reported as the active medium on a terahertz metamaterial device. For this purpose, high-quality few atomic layer MoS2 films with controlled numbers of layers were deposited on host substrates by means of pulsed laser deposition methods. The terahertz conductivity swing in those films is studied under optical excitation. Although no-appreciable conductivity modulation is observed in single-layer MoS2 samples, a substantial conductivity swing, i.e., 0 to ∼0.6 mS, is seen in samples with ∼60 atomic layers. Therefore, although exhibiting much smaller maximum terahertz conductivity than that in graphene, which is a consequence of much smaller carrier mobility, MoS2 can still be employed for terahertz applications by means of utilizing multilayer films. With this in mind, we design and demonstrate optically actuated terahertz metamaterials that simultaneously exhibit a large modulation depth (i.e., >2× larger than the intrinsic modulation depth by a bare MoS2 film) and low insertion loss (i.e., <3 dB). The advantages of using a 2-D material with a bandgap, such as MoS2, rather than a gapless material, such as graphene, are: 1) a reduced insertion loss, which is owed to the possibility of achieving zero minimum conductivity, and 2) an enhanced modulation depth for a given maximum conductivity level, which is due to the possibility of placing the active material in a much closer proximity to the metallic frequency selective surface, thus allowing us to take full advantage of the near-field enhancement. These results indicate the promise of layered 2D materials beyond graphene for terahertz applications.

A Metamaterialized Design for 7th order Type-I Chebyshev LPF

This paper presents a high quality design of a 7th order Type-I Chebyshev low-pass filter (LPF) based on a stepped-impedance (SI) metamaterialized microstrip. The respective methodology involves embedding split ring resonators (SRRs) in addition to complementary split ring resonators (CSRRs) in filter design. The introduced metamaterialized filter manifestd better characteristics than in the conventional filter design and in some other availablefilter designs achieving lower insertion loss and appreciable size reduction. In this metamaterialized filter, miniaturization has been attained through implanting rectangular SRRs on top of the microstrip line besides etching squared CSRRs in its ground plane forming a defected ground structure (DGS). The design shows voltage standing wave ratios (VSWRs) of less than 1.05 in the pass-band interval yielding flattest pass-band with clear impedance matching. The shown group delay (GD) pattern is almost constant of around 0.5ns. Roger substrate material (RO3210) has been utilized with dielectric constant 10.2, substrate thickness 1.27mm, and thickness of microstrip conductor 0.035mm. Simulation outcomes have been obtained using the Ansoft High Frequency Structure Simulator (HFSS) package that is based on finite element method (FEM). The filter is applicable in most microwave (MW) and RF systems.

Designs of low insertion loss optical router and reliable routing for 3D optical network-on-chip

Three-Dimensional Optical Network-on-Chip (3D ONoC) has recently emerged as a high-perfor-mance on-chip communication solution; however, owing to the intrinsic characteristics of photonic devices in existing 3D ONoC, the insertion loss caused by undesirable coupling among optical signals degrades network performance. Considering manufacturing defects and unpredictable noise sources that cause the failure of Optical Routers (ORs) in 3D ONoC, previous work simply abandoned the disabled OR when computing the restore path. In this paper, we propose a new OR structure that reduces insertion loss, and we present the design of a novel adaptive routing algorithm, FTRA-BL, based on the new OR structure with bidirectional waveguides, without abandoning any disabled ORs. Our FTRA-BL selects the normal waveguide in the disabled OR as the backup link so that the best macroscopic restore path can be guaranteed. Simulation results show that our method performs better than previous work in improving transmission reliability and latency.

A novel capacitive loaded structure for miniaturized resonators

ABSTRACTMiniaturized resonators are designed with variable capacitive loading capability by utilizing both sides of the substrates with Printed Circuit Board technology. The proposed design integrates a spiral‐shaped sub‐wavelength inductive element with a parallel plate resonant structure of three variations to achieve notch depths of 37, 39, and 48 dB at 94, 138, and 116 MHz respectively within an area of 6.1 by 9.65 cm2 with reduced insertion losses and narrowed bandwidths. The ratio between the largest dimensions of structure to their guided wavelengths at resonance are all &lt;0.05, demonstrating exceptional compactness of the design without sacrificing the performance of band‐rejection behavior. © 2016 Wiley Periodicals, Inc. Microwave Opt Technol Lett 58:2554–2557, 2016