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Matching Circuit (matching + circuit)
Selected AbstractsFrequency reconfigurable RF circuits using photoconducting switchesINTERNATIONAL JOURNAL OF RF AND MICROWAVE COMPUTER-AIDED ENGINEERING, Issue 1 2010D. Draskovic Abstract Designs for a frequency switchable dual-band branch-line coupler and a reconfigurable S-band power amplifier input matching network with photoconducting switches are presented. Frequency switching is achieved by increasing the power of the laser applied to the highly resistive silicon wafer and changing the properties of silicon under optical illumination. The advantages of this approach are high-speed switching, electromagnetic transparency (no interference), and thermal and electrical isolation between the device and the control circuit. A branch-line coupler frequency shift of 35% and 10% has been achieved from all switches off to all switches on in lower (900 MHz) and upper (1800 MHz) frequency bands, respectively. Frequency switchable class AB power amplifier with silicon switch in the input matching circuit has obtained the frequency tuning range of 2.5,3.5 GHz with no significant loss in efficiency and linearity. © 2009 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2010. [source] Multiband MIMO antenna with independent resonance frequency adjustabilityMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 8 2010Min-Seok Han Abstract A compact multiband multiple-input multiple-output (MIMO) antenna with a band stop matching circuit for next generation mobile applications is proposed. The proposed multiband MIMO antenna consists of two dual-band planar inverted-F antennas, which provide wideband characteristics. To improve the isolation characteristic at the long term evolution band, a band stop matching circuit was inserted at the corner of each antenna element. The proposed MIMO antenna has isolation of ,15 dB at the lower band and over 20 dB at the upper band. In addition, the resonant frequencies of the proposed MIMO antenna can be independently tuned by changing the value of the inductor or by adjusting the widths of Slit1 and Slit2. To evaluate the performance of the proposed antenna, key performance parameters such as total efficiency, envelope correlation coefficient, mean effective gain (MEG), and the MEG ratio are analyzed. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1893,1901, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25334 [source] Small-size coupled-fed shorted T-monopole for internal WWAN antenna in the thin-profile mobile phoneMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2010Wei-Yu Chen Abstract A coupled-fed shorted T-monopole with a small size of 15× 26 mm2 (390 mm2) printed on the system circuit board of the mobile phone for WWAN operation is presented. By using a simple inverted-L feeding strip to capacitively excite the shorted T-monopole, two wide operating bands at about 900 and 1900 MHz, respectively, to cover GSM850/900 and GSM1800/1900/UMTS operations are obtained. The antenna is an all-printing structure, with no external matching circuit on the system circuit board or lumped circuit elements embedded in the antenna required for size reduction or bandwidth enhancement. The antenna is hence easy to fabricate at low cost and is especially suited for thin-profile mobile phone applications. The occupied area (less than 400 mm2) of the antenna printed on the system circuit board of the mobile phone in this study is among the smallest for the internal uniplanar printed antenna capable of penta-band WWAN operation that have been reported. Details of the proposed antenna are described, and the obtained results, including its SAR (specific absorption rate) study, are presented and discussed. © 2009 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 257,262, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.24907 [source] A 1-GHz GaN HEMT based class-E power amplifier with 80% efficiencyMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 11 2008Yong-Sub Lee Abstract This article reports a highly efficient 1-GHz class-E power amplifier based on a GaN HEMT. The compensation elements with a series capacitor and a shunt inductor are used to compensate for the internal parasitic components of the packaged transistor. To improve output power and efficiency by suppressing harmonic powers, an output matching circuit using the transmission lines is used. The peak PAE and drain efficiency of 79.2 and 80.4% with a power gain of 18.14 dB is achieved at an output power of 41.14 dBm for a continuous wave. © 2008 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 2989,2992, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23803 [source] A discussion on the performance of impedance matched antenna system and considerations for a better performanceMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 2 2008Adnan Kaya Abstract Impedance matching networks are used extensively in radio communications. In this study, ,-matching circuit has been used as a matching network. The return loss level of several impedance matched microstrip antennas are compared as a function of matching techniques. The ,-matching device is used to construct the antenna tuning units, which is only used to match the front module and the antenna. This circuit impedance region has been investigated analytically under the variable load condition. When the mismatch is occurred, the result is an increase in the energy consumption or transmission quality deterioration. In addition, the input module in antenna system could be damaged if reflection of the signal levels is excessively high. This is interesting application because antennas cannot be considered alone as component with changing electromagnetic properties. The rectangular microstrip antenna was designed at 2.5 GHz frequency by using microstrip feed line. Better return loss level which is ,16.86 dB has been obtained for this antenna using ,-matching circuit. It is shown that theoretical, simulation, and laboratory results are good agreement. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 50: 410,415, 2008; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.23101 [source] Active integrated antenna for mobile TV signal receptionMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 12 2007Ick-Jae Yoon Abstract This paper proposes a small-sized field-effect transistor (FET) based active integrated antenna (AIA) for terrestrial digital multimedia broadcasting (T-DMB) signal reception, which is one of the mobile TV services allocated to 200 MHz band. The commercially used T-DMB antenna is a 120 mm long monopole, but the size of the proposed one is reduced to 50 mm by the method of active device integration. The active device integrated to the radiator influences not only on the current distribution at the radiator but also the input impedance, results in an antenna size reduction with an enhanced gain. In addition to this, a band-pass filter is designed at the input port of the radiator. This plays a role as a matching circuit between a radiator and an active device as well as provides a band-selection function simultaneously to be free of other high intensity signals existing around the T-DMB band. The antenna effective length related to the same-sized monopole and noise figure are measured to verify the validity of the proposed antenna. The performance of the proposed FET based AIA shows the feasibility of designing absolutely small-sized antenna with active devices integrated compared to an operating frequency band. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 2998,3001, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.22968 [source] A high-efficiency class-E power amplifier using SiC MESFETMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2007Yong-Sub Lee Abstract This article reports a high efficiency class-E power amplifier using a SiC MESFET, which is designed and tested at 2.14 GHz. To improve output power and efficiency by suppressing harmonic powers, an output matching circuit using the transmission lines is used. From measured results for a single tone, the harmonic power levels are maintained below ,58 dBc at a whole output power level. The peak power-added efficiency of 72.3% with a power gain of 10.27 dB is achieved at an output power of 40.27 dBm. © 2007 Wiley Periodicals, Inc. Microwave Opt Technol Lett 49: 1447,1449, 2007; Published online in Wiley InterScience (www.interscience.wiley.com). DOI.10.1002/mop.22455 [source] Internal DTV antenna for folder-type mobile phoneMICROWAVE AND OPTICAL TECHNOLOGY LETTERS, Issue 6 2006Kin-Lu Wong Abstract By using the upper and lower ground planes of a folder-type mobile phone, a novel internal shorted dipole antenna for digital television (DTV) signal reception in the 470,806-MHz band is presented. The shorted dipole antenna further comprises an internal matching circuit, which includes a chip capacitor and two narrow metal strips, for achieving improved impedance matching over the DTV band of 470,806 MHz. The proposed DTV antenna was constructed and studied. The measured return loss for the operating frequencies over the DTV band is better than 2.5:1 VSWR. In addition, good radiation characteristics are also obtained. Design considerations of the proposed internal DTV antenna are described. A parametric study of the internal matching circuit on the impedance matching of the antenna is also presented. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1015,1019, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21587 [source] A compact multilayer diplexer in LTCC substrate using LPF with multiple attenuation poles and wideband BPFELECTRONICS & COMMUNICATIONS IN JAPAN, Issue 5 2010Shimpei Oshima Abstract Recently, compact wideband BPFs for a UWB system have been studied actively. In this paper we propose a compact diplexer built into an LTCC substrate for a UWB system and 2.4-GHz wireless systems. First, a wideband BPF for a UWB system and an LPF with multiple attenuation poles for 2.4-GHz wireless systems are described. Second, we design matching circuits of a common port to retain the basic performance of both the BPF and the LPF. Third, in accordance with the results of the study, we design a compact diplexer built into an LTCC substrate. Finally, we verify the effectiveness of the proposed method by experiments. © 2010 Wiley Periodicals, Inc. Electron Comm Jpn, 93(5): 24,32, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/ecj.10210 [source] Design of transmission line filters and matching circuits using genetic algorithmsIEEJ TRANSACTIONS ON ELECTRICAL AND ELECTRONIC ENGINEERING, Issue 6 2007Hirofumi Sanada Member Abstract A method for designing microwave filters and impedance matching circuits using transmission lines is presented. Transmission line filters with shunt-connected open circuit stubs and continuously varying transmission line matching circuits are described in detail. The proposed method is based on genetic algorithms and can effectively be applied to various filter and matching circuit design problems without increasing theoretical and computational complexity. Design examples are provided, and the proposed method is demonstrated to be effective in designing transmission line filters and matching circuits. Copyright © 2007 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. [source] | ||||||||||