A novel bandpass filter (BPF) based on half-wave-length (λ/2) stepped-impedance resonators (SIRs) is proposed in this paper. By properly designing the impedance ratios of the SIRs, the spurious harmonics of the filter can be pushed to upper frequency. With several bandstop structures such as open stubs and defected ground structures (DGSs) applied to the BPF, a good stopband performance is obtained. Moreover, 0° feed structure is used to improve the selectivity of the BPF. Then a BPF which has high selectivity and wide stopband is implemented. Measured results show good agreement with the simulated results.
A physical model of electron trapping/detrapping in electrically stressed oxide has been proposed in this paper. The new model is based on both inelastic multi-phonon trap-assisted tunneling and thermal emission, and also considers the capture effect of oxide bulk traps. It handles every trap separately, and establishes the dynamic procedure of traps capture and emission of electrons. Finally, through the proposed model we may accurately and effectively obtain the filling state of all the oxide traps at any stress and any time, which is very useful for the modeling of the endurance and data retention characteristics of floating gate nonvolatile memories.
A MIMO antenna with working-frequency-accompanied isolation characteristic is proposed. The MIMO antenna consists of two same monopoles which are printed symmetrically. A complementary split ring resonator (CSRR) is etched on the ground between the two monopoles. The CSRR, which is fed by the monopole through a microstrip line, is the main radiator and isolation structure at the same time. The working and isolation frequencies are influenced by the CSRR equally and always coincide with each other. Two prototypes operating around 5.8 GHz were fabricated and measured. The measured results show that both the fabricated antennas are with return loss of less than 20 and mutual coupling of less than −24 dB. The radiation patterns, gains, efficiencies and envelope correlation coefficient (ECC) were also measured and good performances are achieved.
In this paper, polymer packaged fiber Bragg grating (FBG) sensors are installed inside of the combustor wall to monitor the health of solid rocket motor. The responses of sensor embedded in adhesive specimen composed of propellant, insulation and case when subjected to axial and unaxial tensile stress are investigated. The strain distribution and spectrum of FBG were simulated when the specimen suffered from different normal loadings by finite element method and computer simulation technology. The result is validated by axis and unaxis tensile test. It is shown that the proposed type of sensing system can measure the bond stress (the radial stress) in SRMs.
In this letter, a compact planar ultra-wideband mobile antenna with L-shaped extended ground stubs is presented. The proposed handset antenna consists of two planar meandered monopole radiating elements, i.e., main antenna and auxiliary antenna respectively, located at the diagonal corners of mobile phone printed circuit broad with standard size of 136 × 68 mm2. Each radiating element is composed of two arms and a L-shaped extended ground stub, jointly achieving multiple resonances and ultra-wideband impedance matching with a compact size. The effect of the L-shaped ground stub is investigated in detail. The proposed antenna has a compact size of 31.4 × 12 mm2, printed simple structure and full-band coverage (GSM850 and 1.6–5.4 GHz) for wireless handsets systems, including GSM850, DCS1800, PCS1900, UMTS, LTE, WiMAX, and WLAN in 4G and 5G communication systems. The optimized antenna prototype is fabricated and measured. The measured results show that the reflection coefficients are less than −6 dB over the operating bands and the mutual coupling between two ports is less than −20 dB. Good agreement is obtained between the simulated and measured results. The results demonstrate that the proposed handset antenna has good characteristics of ultra-wideband, isolation, gain, and radiation pattern, and is a good candidate as a terminal antenna for handsets applications.
In this paper, a novel wideband microstrip-fed quasi-Yagi antenna is presented. The proposed quasi-Yagi antenna consists of a microstrip-fed monopole, three radiating patches (two square patches and a rectangular patch), and three parasitic strip elements as the function of reflector. In order to achieve wide bandwidth, two parasitical patches are etched on both sides of the substrate. Furthermore, the stepped microstrip feeding line is adopted so as to get a good impedance matching. A fabricated prototype with the dimensions of 40 mm × 55.5 mm yields a directional far-field radiation pattern with no director, a −10 dB bandwidth (2.21–5.4 GHz) of 83.8% and a peak radiation gain of 4.17 dBi. Finally, the proposed antenna is analyzed, fabricated and measured. Measured and simulated results are in good agreement.
In this paper, a D-band power amplifier (PA) based on 0.5-µm InP DHBT is presented. Wilkinson combiners with broadband stepped-impedance matching are used, and the eight-way PA is designed for wideband power performance. As input power is fixed at 3 dBm, the PA exhibits a saturated output power of 16.8 dBm and 7.9% PAE at 150 GHz with >45-GHz 3-dB power bandwidth from 125 GHz to 170 GHz. Meanwhile the 1-dB gain compression output power is 15.9 dBm at 150 GHz. The >45-GHz 3-dB power bandwidth means a great flatness of power gain which is outstanding in reported D-band PAs to our best knowledge.
A novel microstrip diplexer with novel coupling structure is proposed in this letter. The proposed diplexer is designed with several stepped-impedance resonators. A dual-mode dual-band filter unit is used in this design to replace the conventional matching network, what is more, the dual-mode dual-band filter unit is resonance with other circuit resonator. The diplexer size can be reduced efficiently in this way. The proposed diplexer is composed by two four-pole chevbyshev filters with six stepped-impedance resonators. Based on the structure, a diplexer with the central frequency of 1.89 GHz and 2.35 GHz for 4G wireless communication application is fabricated and measured. Good agreements between measured results and simulated results verify the proposed structure well.