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Microwave Conference, 2001. APMC 2001. 2001 Asia-Pacific

Date 2001

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  • A broadband planar patch antenna fed by a short probe feed

    Publication Year: 2001 , Page(s): 1243 - 1246 vol.3
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (261 KB) |  | HTML iconHTML  

    This paper presents a novel design of a broadband probe-fed planar patch antenna. The proposed antenna has a thick air-layer substrate, and bandwidth enhancement is achieved by cutting a small portion of the ground plane and adding an inverted U-shaped ground plane to be close to the radiating patch, and then feeding the antenna at the inverted U-shaped ground-plane portion using a 50-Ω coax feed with a short probe pin. Prototypes have been successfully implemented, and experimental results show that an impedance bandwidth (1:1.5 VSWR) greater than 20% can be achieved for the proposed antenna. Radiation characteristics of a prototype suitable for application in a DCS cellular system (1710-1880 MHz) base station are also presented. View full abstract»

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  • APMC 2001. 2001 Asia-Pacific Microwave Conference (Cat. No.01TH8577)

    Publication Year: 2001
    Save to Project icon | Request Permissions | PDF file iconPDF (1758 KB)  
    Freely Available from IEEE
  • Author index

    Publication Year: 2001 , Page(s): 1371 - 1376
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    Freely Available from IEEE
  • Development of a novel 38.5 GHz planar Cassegrain antenna

    Publication Year: 2001 , Page(s): 1366 - 1369 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (196 KB) |  | HTML iconHTML  

    The design and results of a novel 38.5 GHz Cassegrain antenna using printed-circuit planar reflectors are presented. This antenna contains a feed patch antenna, a main reflector for twisting and focusing the incident wave, and a sub-reflector for polarization selection. The sub-reflector is made of a PCB printed with a dense metal grid, which is transparent to one polarization but would reflect the other polarization. The main reflector includes hundreds of microstrip antennas which are used to produce twisted reradiation fields and provide phase compensation. This type of antenna has a low-profile configuration and is suitable for mechanical beam scanning View full abstract»

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  • A reflect-array using dual-polarized aperture-coupled microstrip patch antennas

    Publication Year: 2001 , Page(s): 1040 - 1043 vol.3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (279 KB) |  | HTML iconHTML  

    A novel configuration of a dual-polarized reflect-array is investigated. The array uses dual linearly polarized aperture-coupled microstrip patch antenna elements featuring good return losses and large isolation between its orthogonal ports. A 37-element array illuminated by a single dual-polarized aperture-coupled antenna is designed. The developed array shows an increased operational bandwidth. However, its gain is smaller than expected. Investigations into improving the operation of the reflectarray are under way and include accurate characterization of interaction of the antenna element and the stubs for proper phasing, optimising the feed and increasing the array's size View full abstract»

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  • 3-D FDTD design simulation and experimental measurement of a Ka-band planar antipodal linearly-tapered slot antenna (ALTSA)

    Publication Year: 2001 , Page(s): 1271 - 1274 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (248 KB) |  | HTML iconHTML  

    3-D FDTD simulation of a planar broadband Ka-band (25-35 GHz) antipodal linearly-tapered slot antenna (ALTSA) and experimental measurements are presented. The Berenger matched layer absorbing boundary condition (PML-abc) is used for the FDTD computation. A printed ALTSA has been realized by using the RT/Duroid PCB substrate. Good agreement between simulation and measurement is achieved View full abstract»

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  • The effects of path-delay mismatch on GFSK transmitters with a dual-port architecture

    Publication Year: 2001 , Page(s): 1080 - 1083 vol.3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (249 KB) |  | HTML iconHTML  

    In this paper, a low-cost dual-port architecture for GFSK transmitters is investigated for its sensitivity to the path-delay difference between two data ports. The simulation results show that the architecture can achieve a high data rate but encounter significant modulation distortion due to the mismatch in path delay when the frequency deviation is close to the PLL natural frequency View full abstract»

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  • A novel image-rejection amplifier for wireless communications

    Publication Year: 2001 , Page(s): 996 - 999 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (189 KB) |  | HTML iconHTML  

    The theory and design of a high-gain amplifier with image rejection capability is described, where the image rejection is accomplished by placing the transmission zeroes in the impedance match circuitry. The resulting amplifier provides high gain as well as high image rejection ratio. A 5.8 GHz image-rejection amplifier was designed and fabricated to verify the proposed technique. The measured results show 22 dB gain in the ISM band (5.725-5.850 GHz) and at least 43 dB image rejection at the image frequencies of 5.4 GHz and 6.15 GHz, which agree very well with the predicted theory View full abstract»

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  • A novel coupled fed small antenna

    Publication Year: 2001 , Page(s): 1044 - 1047 vol.3
    Cited by:  Papers (1)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (158 KB) |  | HTML iconHTML  

    The characteristics of a single shorting plane with a shorting post L-shaped probe fed antenna and a single shorting plane with a capacitive shorted post L-shaped probe fed antenna are investigated. The patches are designed at a height of about 8.4% of the wavelength The single shorting plane with a shorting post L-shaped probe fed antenna is able to achieve a bandwidth of about 44% and a gain of about 7 dBi. The single shorting plane with a shorting post L-shaped probe fed antenna is able to obtain dual band characteristics View full abstract»

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  • Patch antenna miniaturizing with a shorting pin near the feed probe-its physical mechanism and the design on Smith chart

    Publication Year: 2001 , Page(s): 1048 - 1051 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (205 KB) |  | HTML iconHTML  

    Miniaturizing patch antennas by a shorting pin near the feed probe has been successful in hardware experiments. The physical mechanism is now given. The mechanism points out that a feed probe with the shorting pin is equivalent to a folded dipole antenna in an admittance formula. This equivalence makes it possible to use the Smith chart to: (1) aid the selection of the feed and pin dimensions and (2) provide the limit of possible miniaturization. The mechanism also points out that the efficiency of patch can be quite low due to the high Q of the miniaturized mode View full abstract»

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  • High performance characterization of wireless handset front-end modules

    Publication Year: 2001 , Page(s): 1088 - 1091 vol.3
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (364 KB) |  | HTML iconHTML  

    Multiport, multi-function wireless front-end modules require high performance and high-speed test. A test system and process is developed which provides a state-of-the-art combination of accurate measurements and high throughput at high speeds. This system allows individualized frequency spacing, data taking, and calibration on measurement paths, at speeds up to 10 times faster then previously available. Special test conditions required for high speed testing are presented, along with new uncertainty analysis View full abstract»

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  • Full-wave FDTD analysis of transmission characteristics of a YIG film microstrip line in a nonuniform bias magnetic field

    Publication Year: 2001 , Page(s): 1211 - 1214 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (267 KB) |  | HTML iconHTML  

    Overall transmission characteristics of a microstrip line with a YIG-GGG substrate in a nonuniform bias magnetic field are investigated by using the finite-difference time-domain (FDTD) method including electromagnetic and magnetostatic waves. The FDTD result explains the phenomena of rich transmission peaks caused by the magnetostatic waves in the YIG film microstrip line in a nonuniform bias magnetic field View full abstract»

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  • Reflector shape optimization for FB ratio of dipole antenna

    Publication Year: 2001 , Page(s): 1068 - 1071 vol.3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (197 KB) |  | HTML iconHTML  

    This paper presents the enhancement of FB ratio by optimizing several types of reflector shape which are placed on the back of a dipole antenna for the sector antenna. By optimizing the size of each reflector shape, the FB ratio of dipole antenna is increased by more than 20dB. Comparing each shape for the same width of reflector, a dual box reflector has the best FB ratio of more than 30dB View full abstract»

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  • Application of millimeter waves to measure blood sugar level

    Publication Year: 2001 , Page(s): 1303 - 1306 vol.3
    Cited by:  Papers (3)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (148 KB) |  | HTML iconHTML  

    Measurement of blood sugar level by non-invasive method is desirable. Nevertheless, a practical non-invasive technique has not been reported. In this paper, to measure blood sugar level using millimeter wave non-invasively, complex permittivity of glucose mixed sodium chloride solution is measured and the change of transmission coefficient in millimeter wave region obtained. An applicator system to measure blood sugar level in vivo is designed and optimized by simulation using Transmission Line Modeling (TLM) method View full abstract»

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  • Linearized high efficiency HBT MMIC dual band power amplifier module for L-band applications

    Publication Year: 2001 , Page(s): 1295 - 1298 vol.3
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (287 KB) |  | HTML iconHTML  

    A highly linearized InGaP/GaAs HBT MMIC power amplifier is demonstrated using a linearized active bias circuit for PCS/wide-CDMA dual band applications. The MMIC amplifier has a single matching network and a single bias circuit commonly for the two different bands. The two-stage HBT MMIC power amplifier exhibits a linear power gain of 25.5(24.5) dB, an output power of 28(28) dBm, power added efficiency of 43(37)%, and ACPR of -41(-44) dBc at 1.25(5) MHz offset frequency under 3.0V operation voltage, and consumes quiescent current of 90(90) mA at output power of 0 dBm for PCS(Wide-CDMA) applications. The MMIC chip size with on-chip integrated linearizer and bias circuit is only 0.84mm×1.1mm. The MMIC chip was packaged on plastic substrates, and the power amplifier module size is as small as 6mm by 6mm View full abstract»

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  • Waveguide filter using LTCC

    Publication Year: 2001 , Page(s): 1012 - 1015 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (156 KB) |  | HTML iconHTML  

    A microwave waveguide filter using Low Temperature Co-fired Ceramic (LTCC) is presented. To design the filter, equivalent circuit is applied and Finite Element Method (FEM) is used for simulation. From the result, it is confirmed that the possibility to realize many type of microwave and millimeter wave filter using the LTCC technologies View full abstract»

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  • Optimal feed positions for microstripline-fed rectangular patch antennas by finite difference time domain analysis

    Publication Year: 2001 , Page(s): 1342 - 1345 vol.3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (244 KB) |  | HTML iconHTML  

    This paper applies three dimensional finite difference time domain (FDTD) method to analyze the microstripline-fed rectangular patch antennas while moving the microstripline along nonradiating edges. FDTD analysis is used to find the optimum match position for the microstripline-fed rectangular patch antenna View full abstract»

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  • Far field RCS prediction by near field RCS measurement

    Publication Year: 2001 , Page(s): 1239 - 1242 vol.3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (162 KB) |  | HTML iconHTML  

    The near field system can be used for measuring the performance of antennas and it can also be used for RCS (Radar Cross Section) measurement. The far field patterns for both antenna and RCS can be generated by the transformation of the measured near field data. In this paper the concept of transformation is applied for obtaining the far field RCS of a radar target from the near field measurement data. The processing technique is used to generate the far field RCS pattern. The results of far field RCS by this proposed technique agree quite well with that obtained by direct far field measurement View full abstract»

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  • A low phase-noise oscillator with a planar capacitively loaded microstrip resonator

    Publication Year: 2001 , Page(s): 1092 - 1095 vol.3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (185 KB) |  | HTML iconHTML  

    A low phase noise oscillator incorporated with a capacitively-loaded microstrip resonator was analyzed and designed in the 2 GHz range for wireless communication applications. The planar capacitively-loaded microstrip resonator provides two very close resonances such that its Q value can be dramatically enhanced compared with a single quarter-wavelength microstrip resonator. The measured results shows that the phase noise is effectively reduced to -110 dBc/Hz at 1 kHz off carrier by the capacitively-loaded microstrip resonator View full abstract»

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  • Single-feed triangular microstrip antenna with compact circular polarization

    Publication Year: 2001 , Page(s): 1032 - 1035 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (189 KB) |  | HTML iconHTML  

    The single-feed CP designs of compact triangular microstrip antennas with a triangular slot have been demonstrated. Simply by inserting a narrow slit of proper length at the bottom edge or at the tip of the embedded triangular slot, CP radiation can easily be achieved by using a single probe feed. Results indicate that, at a fixed operating frequency, the proposed designs can have good CP radiation characteristics with a reduced antenna size of about 30% compared to the regular-size CP design using a simple triangular patch View full abstract»

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  • Microstrip line tunable filters using yttrium iron garnet film substrate

    Publication Year: 2001 , Page(s): 1215 - 1218 vol.3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (208 KB) |  | HTML iconHTML  

    Microstrip line tunable filters with a longitudinally magnetized yttrium iron garnet film have been investigated experimentally and theoretically. A half wavelength microstrip line resonator with L-shaped stubs, longer side of which is parallel to the center strip, has been proposed so that attenuation poles are tunable with applied magnetic bias fields and synchronized with the passband, and the experimental results axe compared with the numerical calculation. In addition, we have proposed the composite structure of the above-mentioned resonator and another microstrip line with the same substrate connected in cascade to suppress the unexpected passband due to magnetostatic waves View full abstract»

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  • Simulations of the microwave dielectric filters

    Publication Year: 2001 , Page(s): 1016 - 1019 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (339 KB) |  | HTML iconHTML  

    A microwave resonator filter in a rectangular metallic enclosure with three-dimensional (3D) full-wave analyses is presented. By using 3D finite-element method (FEM) to perform numerical simulations, more accurate parameters and predictions that are hard to be measured but actually affect the performances of a microwave dielectric filter are investigated. Some significant and novel phenomena in this article were first uncovered View full abstract»

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  • A RX cancellation loop configuration for power amplifier module

    Publication Year: 2001 , Page(s): 1199 - 1202 vol.3
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (240 KB) |  | HTML iconHTML  

    A cancellation loop configuration for power amplifier modules is proposed to reject RX signals using a feed-forward technique. In this paper, we implement the 1W-amplifier module to show the validity of the proposed cancellation loop. The power amplifier module can provide low TX insertion path loss due to its duplexer and the choice of loose RX attenuation characteristics for various wireless communication systems. It shows at least 90 % improved RX rejection characteristics compared to power amplifier modules without the RX band cancellation loop View full abstract»

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  • Linear interpolation scheme for compensation of path delay difference in an envelope elimination and restoration transmitter

    Publication Year: 2001 , Page(s): 1072 - 1075 vol.3
    Cited by:  Papers (2)  |  Patents (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (227 KB) |  | HTML iconHTML  

    The linearity of an envelope elimination and restoration (EER) transmitter depends primarily upon the bandwidth of the baseband envelope amplifier and path delay difference between the envelope and phase signals. A method for compensating the path-delay difference based on the baseband DSP technique has been proposed in this paper. This technique uses a baseband interpolation process to reduce the intermodulation effects of an EER transmitter. The improvements in spectral regrowth and waveform quality in the application to an IS-95 reverse link signal are demonstrated View full abstract»

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  • Numerical computation of human body effects on radiation characteristics of loop antennas for watch-type wrist radiophone applications

    Publication Year: 2001 , Page(s): 1307 - 1310 vol.3
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (279 KB) |  | HTML iconHTML  

    Numerical simulation of a full-scale human body model on radiation characteristics of rectangular loop antennas at the wrist position for watch-type radiophone applications is presented. The loop antenna with a superquadric curve is used to model the rectangular loop antenna with rounded comers. The loop antenna may have different position and orientation relative to the wrist. A 3-D realistically shaped man model with homogenous muscle phantom is constructed. The coupled integral equation (CIE's) and the method of moments (MoM) are employed for numerical simulation. Numerical results of detail antenna radiation characteristics in free space and mounted on the wrist of the body with different position and orientation at 900 MHz and 1800 are presented and discussed View full abstract»

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