Search

A low‐loss miniaturized bandpass filter is presented using 3D glass‐based RDL packaging technology. A new topology consisting of one modified Pi‐section and one modified T‐section is introduced to generate three transmission zeros which can achieve the high out‐of‐band rejection. A combination of 2D planar inductors and high‐Q 3D inductors is used to achieve low insertion loss and minimize the filter size. In addition, one grounded resonator at input terminal is introduced to generate an extra transmission zero in the low end. The proposed bandpass filter covering 3.3–4.2 GHz is fabricated with a compact size of 1.6 mm × 0.8 mm × 0.25 mm. It exhibits an insertion loss of less than 1.0 dB at a center frequency of 3.75GHz and a return loss of better than 14 dB. The proposed design has a 3 dB fractional bandwidth of 37.6%. Its out‐of‐band rejection is better than 20 dB at the low frequency band from DC to 2.0 GHz and better than 19 dB at the high frequency band from 5.0 to 9.0 GHz. The simulated and measured results of the proposed BPF are in reasonably good agreement. [ABSTRACT FROM AUTHOR]

A compact bandpass filter (BPF) with wide stopband performance is proposed and implemented on Si‐based integrated passive device (IPD) technology. A modified topology consisting of a novel Pi‐section and two capacitors are introduced in this BPF. The Pi‐section topology can achieve a band‐pass performance and generate four transmission zeros out‐of‐band. These two capacitors can improve the in‐band matching and also widen the stopband. The proposed BPF with a compact size of 1.0 mm × 0.5 mm × 0.3 mm is fabricated using Si IPD technology and measured by on‐wafer probing. It shows that the insertion loss is less than 1.75 dB, the return loss is better than 18 dB in the 5G band, and the upper stopband suppression level is better than 17.5 dB up to 18 GHz. The simulated and measured results of the proposed BPF are in reasonably good agreement. [ABSTRACT FROM AUTHOR]

A miniaturized bandpass filter (BPF) with low insertion loss based on a modified T‐section and a grounded transmission‐zero resonator is proposed. The novel T‐section consists of two resonators, which can achieve the bandpass performance with two transmission zeros (TZs) in the upper band. The grounded transmission‐zero resonator can generate an extra transmission zero in the lower band. Therefore, high frequency selectivity can be achieved by the above three transmission zeros near the passband. The proposed BPF can achieve an insertion loss of 0.8 dB and a return loss of 22 dB covering 3.3–4.2 GHz, and the upper‐stopband attenuation is better than 20 dB up to 12.5 GHz (3.3f0). The proposed BPF with a miniaturized size of 1.2 mm × 0.5 mm × 0.3 mm have been fabricated using Si‐based integrated passive devices (IPDs) technology and measured by on‐wafer probing. The simulated and measured results of the proposed BPF are in reasonably good agreement. [ABSTRACT FROM AUTHOR]

In this letter, a miniaturized bandpass filter (BPF) with controllable transmission zero (TZ) based on one lumped T‐section is proposed. To enhance rejection in the BPF, a modified T‐section circuit is introduced to generate a controllable TZ that can be readily adjusted by the LC values. To validate the performance, the proposed BPF is fabricated using integrated passive device technology on silicon. The measurement results show that the achievable bandwidth covers 2.4–2.5 GHz, with an insertion loss less than 2.6 dB and a measured return loss less than −15 dB. The fabricated BPF has a compact size of 1.3 mm × 0.8 mm (i.e., 0.0113 λ0 × 0.0069 λ0). The simulated and measured results of the BPF are in reasonably good agreement. [ABSTRACT FROM AUTHOR]

This letter proposes a miniaturized integrated passive device (IPD) bandpass filter (BPF) design with high out‐of‐band rejection for 5G applications. In this design, a novel topology based on the modified high‐pass filter cascaded with the modified low‐pass filter is introduced with two pairs of transmission zeros (TZs) at high and low frequencies. In addition, one grounded capacitor at the input is added to improve the suppression at high frequency end. The proposed BPF design is fabricated on silicon substrate. The measured insertion loss is around 3 dB and the return loss is <16 dB in the whole frequency range from 3.3 to 4.2 GHz for 5G applications. This proposed BPF achieves more than 20 dB sideband suppression at both stop bands from DC to 2.69 GHz and from 5.3 to 14 GHz. The fabricated device has a size of only 1 × 0.7 × 0.2 mm. [ABSTRACT FROM AUTHOR]

A miniaturised integrated passive device (IPD) balun design with low insertion loss and balanced amplitude and phase is proposed for Wi‐Fi/Bluetooth applications. In this design, a novel topology based on the modified T‐type filter structure is introduced to offset the parasitic and coupling effects that cause poor balance in IPD design. The proposed balun design is fabricated on a GaAs substrate. The measured insertion loss is lower than 0.9 dB and the measured return loss is >16 dB in the frequency range of 2.2–2.9 GHz. The measured results of amplitude and phase show rather minor imbalances, which are lower than ±0.67 dB and ±1.8° respectively. The fabricated device size is 0.9 mm × 0.6 mm only. [ABSTRACT FROM AUTHOR]

Rice noodles are one of southern people's favorite foods in China, so it is important to find the suitable raw rice for rice noodle making. To study the effects of different rice varieties on the quality of fresh wet rice noodles and to explore the relationship between the quality of the rice and the quality of the fresh wet rice noodles, this study to compare the 12 hybrid rice varieties as raw materials analyzed the differences in the cooking quality, texture index, and sensory score of fresh wet rice noodles using the principal component analysis, membership function, and cluster analysis. The results showed that the quality of fresh wet rice noodles prepared from different hybrid rice materials differed significantly. The fresh wet rice noodles made from Liangyou 5836 are of good quality, and they are mainly characterized by a low rate of broken noodles and spit pulp value, high rice noodle hardness, good rice noodle elasticity, strong rice noodle chewiness, and low adhesiveness. Moreover, its sensory evaluation is also better than that of other varieties. The comprehensive evaluation of 12 hybrid rice varieties by subordinate function analysis also showed that Liangyou 5836 was the best. In addition, through principal component analysis and gray analysis, it was found that 14 related indicators of rice quality and fresh wet rice noodle quality were concentrated into four categories, among which gel consistency best reflects the quality of rice and fresh wet rice noodles. Through comprehensive analysis, it was found that an amylose content of about 22% and a gel consistency of less than 40 mm can be used as core indicators to screen varieties suitable for making rice noodles. This study is of great significance for the selection of hybrid rice for both rice quality and fresh wet rice noodle quality. [ABSTRACT FROM AUTHOR]

This letter proposes a novel compact ceramic cavity bandpass filter with surface silver coating and air coupling apertures. It is constituted of a sextuple‐mode ceramic cavity as the main resonator, two single‐mode cavities to connect the sextuple modes transversely with source and load, and two single cavities to suppress higher harmonics. This proposed filter has the advantages of compact size, wide band, low insertion loss, high selectivity, wide spurious‐free window, as well as coplanar source and load interfaces. There are no blind holes in the filter, which is beneficial for improving the machining accuracy. One prototype filter operating at 3.5 GHz is fabricated and measured. The minimum insertion loss in the passband is 0.65 dB. The inherent spurious mode of the sextuple‐mode resonator at around 1.2fC (fC center frequency) is suppressed under −30 dB. The measured and simulated results are in good agreement. [ABSTRACT FROM AUTHOR]

A novel bandpass frequency-selective surface (FSS) with high selectivity and angular stability is presented. In the skirts of the narrow passband, two transmission zeros (TZs) are generated, leading to the steep roll-offs at both left and right skirts. The realization of two TZs using a single piece of a printed circuit board facilitates the fabrication. The current distribution and equivalent circuit model are given to illustrate the generation mechanism of the TZs. The proposed FSS can achieve good stabilities of polarization and angle. The size of this FSS is $0.15\lambda $. The prototypes of the proposed FSS are fabricated, and good performance is obtained. [ABSTRACT FROM AUTHOR]

A wideband and scalable model of RF CMOS spiral inductors by virtue of a novel space-mapping neural network (SMNN) is presented. A new modified 2-[pi] equivalent circuit is used for constructing the SMNN model. This new modeling approach also exploits merits of space-mapping technology. This SMNN model has much enhanced learning and generalization capabilities. In comparison with the conventional neural network and the original 2-[pi] model, this new SMNN model can map the input-output relationships with fewer hidden neurons and have higher reliability for generalization. As a consequence, this SMNN model can run as fast as an approximate equivalent circuit, yet preserve the accuracy of detailed electromagnetic simulations. Experiments are included to demonstrate merits and efficiency of this new approach. Index Terms--Modeling, neural networks, space mapping, spiral inductor.

A miniaturized high-gain flexible unmanned aerial vehicle (UAV) antenna is presented in this study. The proposed antenna basically comprised of three parts of printed patch in series, etched on dielectric substrate. And, a flexible cable is loaded on the bottom of dielectric substrate. A coplanar waveguide (CPW) with asymmetric ground feeding structure is employed to provide good impedance matching. The surface current can achieve the same phase for the straight-line patch and the flexible cable, through adjusting the dimensions of the meander line patch, which increases radiation gain while maintaining the compact size. As an important merit to be highlighted, the flexible cable can greatly reduce the volume and aerodynamic drag of the antenna. It has a low-profile compact size of 196 × 15 × 0.8 mm3 (excluding flexible cable). The results show that the omnidirectional gain fluctuates within 4.5 ± 0.1 dBi in the desired band (902 MHz–928 MHz), which is high enough for the UAV application. Details of the antenna design and experimental results are presented and discussed. [ABSTRACT FROM AUTHOR]

A novel ultrawideband low-profile high-efficiency indoor antenna formed by the printed slotted patches with lumped elements loading technique is presented. By loading the parallel and series resistors, the surface current of the proposed antenna is distributed in a traveling wave, thereby effectively widening the impedance bandwidth of the antenna. By loading the inductor, the radiation efficiency of the antenna is improved while maintaining the compact size. The proposed antenna can cover 0.1 G–3 GHz ultrawideband width and has high efficiency in the whole frequency band. Moreover, the proposed antenna has a low-profile compact size of 310 × 270 × 0.8 mm3. Good omnidirectional radiation characteristics are achieved over the entire frequency range. Details of the antenna design and experimental results are presented and discussed. [ABSTRACT FROM AUTHOR]

A new compact multiband planar antenna combining an interdigital-coupled feeding line and one stepped-impedance structure is presented here. This antenna is capable of generating five resonant modes to cover the ISM 915/2400/5800 MHz bands, GPS band, and IMT C-band, respectively. The five resonant frequencies covered by the proposed antenna can be adjusted individually by controlling the impedances and electrical lengths of the corresponding stepped-impedance sections. An additional advantage of the proposed stepped-impedance structure is its ability to suppress higher order resonance modes, thus filtering out unwanted interference. The proposed antenna utilizes a simple planar compact structure and occupies a small area of only 12 × 30 mm2. Details of the antenna design and experimental results are presented and discussed. [ABSTRACT FROM AUTHOR]

A novel high-efficiency compact planar antenna at 433 MHz with minimized size and low-cost and easy to integrate into the ISM wireless applications is designed, fabricated, and measured. Capacitive strips that are formed by cutting inter-digital slots and the meander lines on both sides are introduced to greatly reduce the antenna size yet maintain the high efficiency. The proposed antenna has a simple planar structure and occupies a small area (i.e., 45 × 30 mm2). This novel electrically small antenna can be operated well without any lumped elements for impedance matching. Details of the antenna design and experimental results are presented and discussed. [ABSTRACT FROM AUTHOR]

This paper presents a novel sensitivity-analysis-based adjoint neural-network (SAANN) technique to develop parametric models of microwave passive components. This technique allows robust parametric model development by learning not only the input–output behavior of the modeling problem, but also derivatives obtained from electromagnetic (EM) sensitivity analysis. A novel derivation is introduced to allow complicated high-order derivatives to be computed by a simple artificial neural-network (ANN) forward-back propagation procedure. New formulations are deduced for exact second-order sensitivity analysis of general multilayer neural-network structures with any numbers of layers and hidden neurons. Compared to our previous work on adjoint neural networks, the proposed SAANN is easier to implement into an existing ANN structure. The proposed technique allows us to obtain accurate and parametric models with less training data. Another benefit of this technique is that the trained model can accurately predict derivatives to geometrical or material parameters, regardless of whether or not these parameters are accommodated as sensitivity variables in EM simulators. Once trained, the SAANN models provide accurate and fast prediction of EM responses and derivatives used for high-level optimization with geometrical or material parameters as design variables. Three examples including parametric modeling of coupled-line filters, cavity filters, and junctions are presented to demonstrate the validity of this technique. [ABSTRACT FROM AUTHOR]

A novel parametric modeling technique is proposed to develop combined neural network and transfer function models for both time and frequency (TF) domain applications of passive components, where the neural network is trained to map geometrical variables to the coefficients of transfer functions. Built on our previous work, a new order-changing module is developed to enforce stability of transfer functions and simultaneously guarantee continuity of coefficients. A constrained optimization strategy is introduced to enforce passivity of transfer functions through a neural network training process. A general equivalent circuit for two-port passive components is generated directly from coefficients of arbitrary-order transfer functions. Once trained, the parametric model can provide accurate and fast prediction of the electromagnetic behavior of passive components with geometrical parameters as variables. Compared to our previous work, the proposed method enables models to work well in the time domain providing good accuracy in challenging modeling applications. Two parametric modeling examples of spiral inductors and interdigital capacitors, and their application in both time and frequency domain simulations of a power amplifier are examined to demonstrate the validity of the proposed technique. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE , 2013. [ABSTRACT FROM AUTHOR]

This paper describes a novel method of modeling the differential via on multilayered printed circuit boards (PCBs) used in high-speed digital designs based on the analytical equations for characteristic impedance and effective dielectric constant. In the absence of measured or electromagnetic simulated data traditionally needed to extract these parameters, this method can quickly and efficiently predict the behavior of the differential via holes on PCBs using a circuit simulator. [ABSTRACT FROM PUBLISHER]

This letter presents a simple and efficient high-dimensional parametric model of microwave cavity filters utilizing a modular neural network technique. The filter structure is decomposed into several parts, and a set of neural networks are trained to learn the behavior of the filter parts. These neural networks considered as submodels, are then combined and incorporated into the final model structure. A frequency-space mapping module is introduced to align the combined model to match the overall filter behavior. The proposed method allows the overall model be developed with limited training data of the overall filter. Once trained, the model provides an accurate and fast prediction of EM behavior of filters with high-dimensional geometry parameters as variables. The proposed model is used for fast design optimization of filters. Numerical examples and comparisons with direct EM simulation and optimization are included to demonstrate the merits of the proposed technique. [ABSTRACT FROM PUBLISHER]