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ABSTRACT: In this paper, a miniaturized 18–40GHz sub-harmonic mixer is designed and implemented with 0.15μm GaAs pHEMT process. The
proposed mixer employs anti-parallel diode pair with parallel to ground configuration, and a novel coupler structure to feed
RF and LO signals, resulting in broadband performance and compact chip size. The measured conversion loss is 10.3–13.5dB
in a wide operation frequency band of 18–40GHz. The chip size is 0.66mm2.
KeywordsSub-harmonic mixer-Coupler-pHEMT
Journal of infrared, millimeter and terahertz waves 04/2012; 31(6):690-696. · 0.74 Impact Factor
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ABSTRACT: A printed log-periodic dipole antenna (PLPDA) with multiple notched bands is proposed for ultrawideband (UWB) applications. The impedance bandwidth of 3.1 GHz-10.6 GHz with VSWR less than 2 is achieved based on the wideband property of the PLPDA as well as the half mode substrate integrated waveguide (HMSIW) Balun. Different from omnidirectional UWB antennas, the end-fire radiation pattern of the PLPDA is more stable within the UWB band. Multiple notched bands are generated by integrating U-shaped slots into the PLPDA for blocking the interference from other narrow band wireless communication systems. Several antennas with the notched frequencies of 3.5 GHz, 5.5 GHz, 6.8 GHz, and 8.5 GHz are designed, fabricated, and measured. The measured results are in agreement with the predicted results.
IEEE Transactions on Antennas and Propagation 04/2011; · 2.15 Impact Factor
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ABSTRACT: In this paper, a planar 180 phase-reversal T-junction and a modified magic-T using substrate integrated waveguide (SIW) and slotline are proposed and developed for RF/microwave applications on the basis of the substrate integrated circuits concept. In this case, slotline is used to generate the odd-symmetric field pattern of the SIW in the phase-reverse T-junction. Measured results indicate that 0.3-dB amplitude imbalance and 3 phase imbalance can be achieved for the proposed 180 phase-reversal T-junction over the entire -band. The modified narrowband and optimized wideband magic-T are developed and fabricated, respectively. Measured results of all those circuits agree well with their simulated ones. Finally, as an application demonstration of our proposed magic-T, a singly balanced mixer based on this structure is designed and measured with good performances.
IEEE Transactions on Microwave Theory and Techniques 02/2011; · 1.85 Impact Factor
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ABSTRACT: Two types of substrate integrated waveguide (SIW) long slot leaky-wave antennas with controllable sidelobe level are proposed and demonstrated in this paper. The first prototype is able to achieve an excellent sidelobe level of -27.7 dB by properly meandering a long slot etched on the broadside of a straight SIW section from the centerline toward the sidewall then back. But it is known that an asymmetrically curved slot would worsen the cross-polar level. To overcome this drawback, a modified leaky-wave antenna is proposed, which has a straight long slot etched on the broadside of a meandering SIW section. It yields an outstanding sidelobe level of -29.3 dB and also improves the cross-polar level by more than 11 dB at 35 GHz. Experimental results agree well with simulations, thus validating our design. Then, a two-dimensional (2-D) multibeam antenna is developed by combining such 14 leaky-wave antennas with an SIW beamforming network (BFN). It has features of scanning both in elevation orientation by varying frequency and in cross-plane direction by using the BFN. Excited at ports 1-10 of such a 2-D multibeam antenna at 35 GHz, angular region of 86.6° in azimuth can effectively be covered by 3 dB beam-width of ten pencil beams. Varying frequency from 33 GHz to 37 GHz, the angular region of 37.5° and 38.9° in elevation can be covered by 3 dB beam-width of those continuous scanning beams excited at ports 6 and 8 respectively.
IEEE Transactions on Antennas and Propagation 02/2011; · 2.15 Impact Factor
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ABSTRACT: In this invited paper, some recent research advances in the miniaturization of substrate integrated bandpass filters in the state key laboratory of millimeter waves (SKLMMW) are reviewed.
Microwave Conference Proceedings (APMC), 2010 Asia-Pacific; 01/2011
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ABSTRACT: The transition from radiative to guiding behavior of a half-mode substrate integrated waveguide (HMSIW) is studied throughout this work. The electric near-field distribution in the substrate plane is first demonstrated at different frequencies over the mono-mode operation band and is then related to far-field radiation patterns. The observation shows that the HMSIW, as a semi-open transmission line, suffers from relatively large radiation loss as it operates at frequencies just above the cut-off. However, the radiated power drops drastically with the increase of frequency. In particular, the attenuation caused by radiation becomes negligible as the frequency increases beyond a critical point. An explanation is given to the phenomena above and an approximate equation is also proposed for estimating the critical frequency point, as low-frequency limit of the HMSIW operational range. These results provide a physical confirmation of the optimal operation frequency range for the use of HMSIW as a low-loss waveguide.
Microwave Conference Proceedings (APMC), 2010 Asia-Pacific; 01/2011
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IEICE Transactions. 01/2011; 94-B:342-345.
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Proceedings of the 73rd IEEE Vehicular Technology Conference, VTC Spring 2011, 15-18 May 2011, Budapest, Hungary; 01/2011
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Proceedings of the 74th IEEE Vehicular Technology Conference, VTC Fall 2011, 5-8 September 2011, San Francisco, CA, USA; 01/2011
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ABSTRACT: In this paper, an X -band low phase-noise voltage-controlled oscillator (VCO) using a novel electronically tunable substrate integrated waveguide (SIW) resonator is proposed and developed for RF/microwave applications on the basis of the substrate integrated circuits concept. In this case, the resonant frequency of the SIW cavity resonator is tuned by different dc-biasing voltages applied over a varactor coupled to the cavity. Measured results show that the tuning range of the resonator is about 630 MHz with an unloaded Q U of 138. Subsequently, a novel reflection-type low phase noise VCO is developed by taking advantage of the proposed tunable resonator. Measured results demonstrate a frequency tuning range of 460 MHz and a phase noise of 88 dBc/Hz at a 100-kHz offset over all oscillation frequencies. The VCO is also able to deliver an output power from 6.5 to 10 dBm. This type of VCO is very suitable for low-cost microwave and millimeter-wave applications.
IEEE Transactions on Microwave Theory and Techniques 01/2011; · 1.85 Impact Factor
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ABSTRACT: A novel printed side shaped elliptical monopole with ultra-wide bandwidth is presented in this paper. The antenna is simulated with CST software and fabricated on a Rogers 5880 dielectric substrate. The measured impedance bandwidth with VSWR<;2 is from 0.8GHz to 6.3GHz. The short axis of the elliptical radiator is reduced for compact designation, and two notches at the sides of the ellipse are introduced for improving the radiation patterns.
Signals Systems and Electronics (ISSSE), 2010 International Symposium on; 10/2010
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ABSTRACT: In this letter, dynamic fuzzy neural networks (D-FNN) are applied to model power amplifiers (PAs) with memory effects. The D-FNN model implements Takagi-Sugeno-Kang (TSK) fuzzy systems based on extended radial bias function (RBF) neural networks. The parameters of the model are trained by the online self-organized learning algorithm, in which the neurons can be recruited or deleted dynamically according to their significance to system performance, and the over fitting or over training problems can be avoided. The D-FNN model is validated in our test bench in which a Doherty PA is excited with 10 MHz and 20 MHz worldwide interoperability for microwave access (WiMAX) signals. Experimental results show that the D-FNN model can give an accurate approximation to characterize the wideband PAs with memory effects.
IEEE Microwave and Wireless Components Letters 10/2010; · 1.72 Impact Factor
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ABSTRACT: In this work we present a systematic approach for designing planar lenses using artificial dielectrics to realize the desired phase delays. The artificial dielectric is synthesized by using multilayer frequency selective surfaces (FSSs) with Jerusalem Cross (JC) elements, because they are found to be good candidates that provide stable response over a wide range of incident angles and for both polarizations.
Antennas and Propagation Society International Symposium (APSURSI), 2010 IEEE; 08/2010
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ABSTRACT: Dielectric resonator antennas (DRAs) fed by a halfmode substrate integrated waveguide (HMSIW) are proposed and studied in this paper. The investigated antenna configuration consists of a dielectric resonator (DR) mounted on the conducting back plane of an HMSIW. Energy is coupled from the interior HMSIW to the DR through an aperture between them. Using this excitation scheme, a 60 GHz linearly polarized HMSIW-fed DRA is first designed by applying a transverse rectangular slot to feed a dielectric cylinder. This design experimentally exhibits a bandwidth of 24.2% for S<sub>11</sub> < -10 dB. In particular, a gain higher than 5.5 dB and a radiation efficiency between 80% and 92% are obtained over the whole operation band, indicating that the HMSIW can be an efficient feed for DRAs operating around 60 GHz. In addition to this linearly polarized example, a DRA of circular polarization, coupled through a pair of cross slots, is also designed, presenting a measured 3-dB axial ratio bandwidth of 4.0%.
IEEE Transactions on Antennas and Propagation 07/2010; · 2.15 Impact Factor
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ABSTRACT: A millimeter-wave frequency scanning antenna, which is capable of dynamically changing the state of polarization thereby providing four modes of operation, is investigated and synthesized in the half mode substrate integrated waveguide (HMSIW) technology. This antenna is a planar passive circuit and fabricated by the low-cost PCB process. It is able to operate in either linear or circular polarization (LP or CP), depending on the requirements of its specific application. A wide angular region can be covered by 3 dB beam-widths of the continuous scanning LP beams and CP beams varying the frequency. It has good performance validated by measurements and has nearly a half reduction in size compared with the substrate integrated waveguide (SIW) version. The axial ratios of CP modes are excellent in the main beam directions within whole frequency band of interest and the isolations between each channel are good as well.
IEEE Transactions on Antennas and Propagation 07/2010; · 2.15 Impact Factor
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ABSTRACT: In this paper, a modified magic-T using substrate integrated waveguide (SIW) and slotline is proposed and developed for RF/microwave applications on the basis of the substrate integrated circuits (SICs) concept. The modified planar magic-T consists of an 180° phase-reversal T-junction and an H-plane SIW T-junction. An optimized wideband magic-T structure is demonstrated and fabricated. Measurement of this structure shows very promising results. Also, theoretical analyses are presented and discussed with transmission line models of the modified magic-T. Measured results of the circuit agree well with its simulated ones.
Microwave Symposium Digest (MTT), 2010 IEEE MTT-S International; 06/2010
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ABSTRACT: This paper overviews the state-of-the-art of the substrate integrated waveguide (SIW) techniques in the design and realization of innovative and low-loss millimetre-wave antenna arrays and beamforming networks for low-cost satellite and mobile systems. Novel classes of SIW-based antenna and beamforming techniques on the basis of this concept of substrate integrated circuits (SICs) are demonstrated to offer unprecedented performances and opportunities. Different structures and architectures are theoretically and experimentally studied and discussed for specific space- and ground-based applications. High-density integration and high-volume manufacturing issues are addressed.
Antennas and Propagation (EuCAP), 2010 Proceedings of the Fourth European Conference on; 05/2010
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ABSTRACT: A novel frequency selective surface based on substrate integrated waveguide technology (SIW) is proposed and studied theoretically and experimentally. Its primary function is the selection of a linear polarization of an incident wave and its 90-degree rotation in a given frequency band. The proposed structure is based on an SIW cavity, coupled to the input and output by two orthogonal slots, and is designed using a simulation code based on the method of moments boundary integral-resonant mode expansion method, especially developed for the accurate characterization of FSS structures. Moreover, a complete design procedure for the proposed structure and a parametric study of its performance are presented. Finally, in order to verify the proposed structure, a prototype is designed at an operation frequency of 35 GHz, exhibiting a relative bandwidth of 9.1% and an impedance matching of better than -11 dB with a maximum insertion loss of 0.2 dB in the passband. Its performance is investigated in detail including the analysis of non-orthogonal incidence angles.
IEEE Transactions on Antennas and Propagation 05/2010; · 2.15 Impact Factor
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ABSTRACT: In this paper, a broadband self-compensating phase shifter is presented and developed on the basis of substrate integrated waveguide (SIW) technology. Since the SIW is a dispersive guided-wave structure, the effective bandwidth of SIW phase shifter is usually narrow. Phase shifts generated by two different structures, namely delay line and equal-length unequal-width phase shifter, are discovered in this work to present interesting opposite tendencies versus frequency. Therefore, an appropriate combination of them will make the phase shift almost constant over a very wide band. Design equations and process are given following a mathematical analysis. To demonstrate the interesting and useful features of the proposed technique, a 90?? and a 45?? self-compensating phase shifters are designed as showcases with standard printed circuit board process. For the 90?? version, the measured amplitude and phase imbalance between the two paths are within 0.2 dB and 2.5?? , respectively, within the frequency band from 25.11 to 39.75 GHz, or around 49% bandwidth. The return loss is found to be better than 12 dB within the frequency band of interest. The 45?? one has the similar excellent performance. The measurements demonstrate that this type of SIW phase shifter is superior to all of its counterparts.
IEEE Transactions on Microwave Theory and Techniques 02/2010; · 1.85 Impact Factor
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ABSTRACT: This paper presents a novel electronically tunable substrate integrated waveguide (SIW) cavity resonator at microwave frequency. The resonant frequency of the cavity is tuned with different DC biasing voltages applied over a varactor coupled to the cavity. This structure has been analyzed with a full-wave software package. To validate our analysis, an X-band reflective tunable SIW cavity resonator is designed and fabricated as an experimental example. Measured results show that the tuning range of the resonator is about 160 MHz with loaded Q<sub>L</sub> of 150. The proposed resonator can be used to design tunable devices such as microwave and millimeter-wave voltage controlled oscillator (VCO).
Microwave Conference, 2009. APMC 2009. Asia Pacific; 01/2010
