Chien-jen Wang

ABSTRACT An active-integrated dual-beam scanning leaky-wave antenna design is developed in this paper. A varactor-tuned HEMT VCO as an active source, integrates with an X-band two-terminal asymmetrically feeding microstrip leaky-wave antenna on the same plane. This approach creates a dual-beam radiation pattern and has the advantages of multi-direction and no reflected wave caused by the open end of the radiating element, as compared to a traditionally single-terminal feeding leaky-wave antenna. Measured results on the experimental antenna show that the total scanning angle of two beams of this antenna configuration is approximately 44°. The maximum Effective Isotropic Radiated Power (EIRP) are close to 17.5 dBm for the right beam and 16.67 dBm for the left beam at 10.4-GHz, and the power difference between the two beams is less than 1 dB

A new design of a miniaturized microstrip helical antenna is proposed and presented for mobile communication. The antenna-size reduction is achieved by folding the simple microstrip line around a substrate. The measured data shows that this microstrip antenna provides wide bandwidth and the multiband characteristics. The bandwidth at 1.8 GHz is approximately 140 MHz. The co-polarized far-field radiation pattern of this antenna is quasi-omnidirectional. Details of the antenna design and experimental results are described and discussed

Here, we present a method to suppress the back lobe of a short leaky-wave antenna by using an aperture-fed patch antenna on the backside. The aperture-fed patch antenna is connected to the open end of the leaky-wave antenna (LWA). Such a design offers another radiation path of the reflected wave and creates another radiation pattern on the back plane of the substrate. Experimental results show that the suppression of the reflected wave can be 10 dB at 10.0 GHz with an LWA length of 6 cm (2 wavelengths). The suppression bandwidth is 200 MHz owing to the narrow bandwidths of the aperture and patch. Compared to conventional designs, this novel structure can radiate as efficiently as an LWA with a length of 4 wavelengths. The two radiation patterns on the different planes have great potential in many applications and provide more flexibility than traditional designs.

Few studies have examined the association between environmental phthalate exposure and children's neurocognitive development. This longitudinal study examined cognitive function in relation to pre-and postnatal phthalate exposure in children 2-12 years old. We recruited 430 pregnant women in their third trimester in Taichung, Taiwan from 2001-2002. A total of 110, 79, 76, and 73 children were followed up at ages 2, 5, 8, and 11, respectively. We evaluated the children's cognitive function at four different time points using the Bayley and Wechsler tests for assessing neurocognitive functions and intelligence (IQ). Urine samples were collected from mothers during pregnancy and from children at each follow-up visit. They were analyzed for seven metabolite concentrations of widely used phthalate esters. These esters included monomethyl phthalate, monoethyl phthalate, mono-butyl phthalate, mono-benzyl phthalate, and three metabolites of di(2-ethylhexyl) phthalate, namely, mono-2...

A beamforming technique for leaky-wave antennas (LWA) which can switch electronically in three different radiation patterns on the H plane has been developed. A simple two-terminal feeding microstrip-line LWA works as a radiating element. By varying the phase of the two injection signals from 0, 90 to 180 degrees, the emitting power from the LWA can produce three different radiation modes: the normal mode (one sharp beam), the difference mode (Δ) and the sum mode (Σ). The antenna displays large-bandwidth characteristics and can be useful near crossroads for collision avoidance, or in the radiolocation of vehicles

In this paper, an active-integrated leaky-wave antenna with power combining scanning capability is presented. This leaky-wave antenna with the novel perpendicular L-shape topology is integrated with a varactor-tuned high-electron mobility transistor (HEMT) voltage controlled oscillator (VCO) on the same plane. Changing the VCO frequency, we can control not only the dual-beam scanning angle but also derive the power combining effect with the sum (Σ) or difference (Δ) radiation patterns. The power combing effect of difference mode, which is the dual-beam pattern and the sum mode pattern, which is a 3-beam pattern, with the 3rd beam located along the middle direction (45°, 135°) of the X and Y axes. The measured scanning angle is steered over a range of 24-46° for the right beam and 127-148° for the left beam. Compared with single microstrip leaky-wave antenna, the L-shape LWAs configuration has the advantages of switchable radiation patterns as the VCO varied from 10GHz to 10.6GHz.

A new design of open-slot antenna with a high front-to-back (F/B) gain ratio is proposed in this work. In order to enhance unidirectional radiation characteristics of the open-slot antenna, a two-element array and a pair of symmetrical notched slits are utilized. The two-element array achieves a power combination and increases the front-endfire radiation gain. The pair of symmetrical slits acts as a power reflector, which suppresses the backward radiating power. In addition, three arrays of eight-element metal strips are added and used as a power director so that the forward power and the F/B ratio of the open-slot antenna can enhance. From the measured results, the proposed antenna demonstrates a F/B ratio of 22.3 dB and possesses superior unidirectional radiation performance.

The frequency response characteristics, such as resonance condition and spurious harmonic, of a mallet-like slotted-ground-plane resonator have been shown in this work. Unlike the conventional slotted-ground-plane resonator with a half wavelength, the length of this proposed structure is only quarter-wavelength long so that compactness can be achieved. The technique of size reduction for the resonator is furthermore presented by modifying the impedance ratio of the mallet-like slot segments. Owing to the semi-ground plane, decrease of the quality factor causes enhancement of the rejection bandwidth. We analytically derive design equations with respect to the impedance ratio of the mallet-like slot resonator and can predict resonant modes without utilizing EM simulation software. In addition, by utilizing the thru-reflect-line calibration technique and theoretical methods, parameter extraction of the equivalent circuit of the mallet-like open-slot resonator is presented.

In this study, a small dipole antenna for digital television (DTV) reception band (470-862 MHz) is developed. The antenna is composed of a pair of bent dipoles, which are coupling fed by a coaxial cable. The resultant antenna has compact size of 20×200×0.8 mm3. Two parasitically coupling strips are added to excite one additional resonance mode. Bent dipole antennas and feeding structures are fabricated on the different planes of the substrate to embed two L-shaped stubs, thus resulting in improvement of the impedance matching condition. After careful optimization of the geometrical parameters of the antenna, the resonances are merged and thus, a wide impedance bandwidth is obtained. The measured -6-dB bandwidth of the antenna in free space is 615 MHz (80.4%).

ABSTRACT A wideband planar antenna with unidirectional characteristics is demonstrated based on the monopole slot antenna. By utilizing a stub-protruded feedline and adding two symmetrical stubs at the slot edge, the impedance-matching condition is improved. The resonance frequency of the monopole slot antenna is significantly shifted down, and the impedance bandwidth is enlarged. By changing the width of the ground plane, connecting one metallic finger at the upper right corner, and etching two asymmetrical slits in the ground plane as reflectors, the radiation directivity of the monopole slot antenna can be enhanced. The proposed antenna achieves a measured 97.4 % bandwidth for S11 < -10 dB at the center frequency of 2.31 GHz, better than 10 dB front-to-back ratio. I. INTRODUCTION A quarter-wavelength open slot cut in the finite ground plane and fed by a microstrip transmission line, a wide impedance bandwidth and bi-directional radiation are provided [1]. Several different slot shapes were introduced to generate additional resonances so that bandwidth enhancement was achieved [2]. Furthermore, the occupied area of the antenna was decreased. In [3], a pentagon-shape slot was etched as a radiator on the ground plane, and a feeding line with a pentagon stub was used. This antenna demonstrates a superior ultra-wideband (UWB) impedance bandwidth. A multiband monopole slot antenna utilized in wireless wide area network (WWAN) application was studied in [4]. In this paper, we etched two slits of different lengths in the ground plane of the monopole slot antenna in order to decrease the back radiation. Techniques such as adding one finger stub at the upper right corner and changing the ground geometry are also utilized to enhance the front-to-back (F/B) ratio of the co-polarized radiation in the operated band. A stubprotruded feeding structure and two identical rectangular stubs inserted into the radiated region are used in order to improve the impedance matching condition.

ABSTRACT A CPW band-selective antenna module has been designed and demonstrated in this paper. The out-of-band signals are rejected before the LNA such that the noise figure of the communication systems could be reduced. The tested antenna module, including the broadband CPW-fed spiral slot antenna and the CPW filter, can filter out the out-of-band signals such that the noise figure can be decreased

ABSTRACT Design procedures of two-element monopole slot antenna arrays are presented in this paper. We proposed several array topologies utilizing different feeding structures and injecting in-phase or out-of-phase signals to achieve power-combining radiation patterns. The sum and difference radiation patterns are successfully achieved and are theoretically analyzed. Furthermore, the power-combining characteristics are also presented by two proposed antenna arrays. The proposed antenna arrays can be candidates of the radiator for the base station or access point of the wireless local area network system.

ABSTRACT In this paper, a wideband CPW-fed slot antenna based on the L-shaped is proposed. In order to simplify the antenna configuration and fabrication process, the slot antenna and the feeding structure are etched on the same plane of the substrate. By changing the geometry of the L-slot, an additional mode with two orthogonal electrical fields with 90 degree phase difference is excited, thus causing the circularly polarization (CP). Furthermore, introducing a protruded stub at the feedline, adding one finger slit and tuning the dimension of the ground plane improve the impedance matching condition. Finally, after the size optimization, the measured bandwidth of 22% (2.23-2.78 GHz) is achieved with an axial ratio

Inhibition of 17α-hydroxylase/17,20-lyase (CYP17), which dictates the proceeding of androgen biosynthesis, is recommended as an effective treatment for androgen-dependent diseases. However, androgen depletion by selective CYP17 inhibition is accompanied with corticosteroid elevation, which increases risk of cardiovascular diseases. In this study, we evaluated the likelihood of polyphenols as a CYP17 inhibitor without cardiovascular complications. All examined polyphenols significantly inhibited CYP17 in human adrenocortical H295R cells, but their effects on androgen and cortisol biosynthesis were diverse. Resveratrol was the most potent CYP17 inhibitor with an approximate IC50 of 4 μM, and the inhibition might weigh on the 17α-hydroxylase activity more than the 17,20-lyase activity. Resveratrol also inhibited 21α-hydroxylase (CYP21) essential for corticosteroid biosynthesis but to a lesser extent, thus preventing the occurrence of cortisol elevation following CYP17 blockade. Althoug...

A beam-switchable scanning leaky-wave antenna (LWA) integrated with p-I-n diode switch circuits has been developed in this paper. This LWA with a two-terminal feeding microstrip line structure is integrated with a SPDT (single port double throw) switch as a control circuit. Compared with traditional leaky-wave antennas, this configuration offers the advantage of one/dual beam scanning radiation pattern. On the dual-beam

ABSTRACT In this paper, an active-integrated leaky-wave antenna with power combining scanning capability is presented. This leaky-wave antenna with the novel perpendicular L-shape topology is integrated with a varactor-tuned high-electron mobility transistor (HEMT) voltage controlled oscillator (VCO) on the same plane. Changing the VCO frequency, we can control not only the dual-beam scanning angle but also derive the power combining effect with the sum (L) or difference (A) radiation patterns. The power combing effect of difference mode, which is the dual-beam pattern and the sum mode pattern, which is a 3-beam pattern, with the 3rd beam located along the middle direction (450, 1350) of the X and Y axes. The measured scanning angle is steered over a range of 24-460 for the right beam and 127-1480 for the left beam. Compared with single microstrip leaky-wave antenna, the L-shape LWAs configuration has the advantages of switchable radiation patterns as the VCO varied from 10GHz to 10.6GHz.

This paper demonstrates the implementation of a responsive window which consists of an LCD-TV display and an ultrasonic location system. The window is perceptive because the main controller detects the location of the front observer by an ultrasonic system. The controller also manipulates the remote-end IP-camera to give a proper view which is corresponding to the location of the observer.

Abstract—This paper presents a circularly polarized (CP) GPS/DCS loop-like antenna with a microstrip feed. The proposed antenna comprised of a quasi-C antenna, an inverted-L sleeve strip connected with the ground plane and an L-shaped slit embedded in the ground ...

For the emerging and rapidly wireless communication systems, both miniaturization and multiband (or wideband) operation of antennas are essential and attractive. Because of their advantages of low profile and light weight, printed antennas have become the like choice of ...

ABSTRACT This paper proposes a dual-band circular polarization (CP) monopole antenna. This antenna can generate a broadband impedance-bandwidth from 2.17 to 8.47 GHz, and excite a left-hand circular polarization (LHCP) at 2.48 GHz and right-hand circular polarization (RHCP) at 3.90 GHz. The measured 3-dB axial ratio (AR) bandwidths are about 140 MHz from 2.41 to 2.55 GHz approximately 5.6% with respect to the center frequency at 2.48 GHz and 900 MHz from 3.45 to 4.35 GHz approximately 23.1% with respect to the center frequency at 3.90 GHz.

Page 1. A Microstrip-fed Circularly-Polarized Loop-like Antenna Chia-Hsien Lin *1 , Jin-Wei. Wu 2 , Tong-Chia Chiou 1 , Chih-Hsing Chen 1 and Chien-Jen Wang 1 (1) Department of Electronics Engineering, National University of Tainan, 33, Sec. 2, Shu-Lin St., ...

ABSTRACT A new design of the dual-band monopole antenna with the strip-line topology has been shown in this study. The dual-band characteristics are achieved using several strip monopole radiators. A small planar inverted-F monopole antenna (PIFMA) is connected to the ground plane. The bandwidth improvement for the antenna is obtained mainly by modifying the geometrical configuration of the strip monopoles added at the antenna and the ground plane. The measured results of the impedance-bandwidth are about 44 MHz (458 to 502 MHz) and 118 MHz (701 to 819 MHz).

SUMMARY Active frequency-tuning beam-scanning leaky- mode antenna arrays have been demonstrated in this paper. These antennas integrated one or several microstrip leaky-wave antenna elements with a single varactor-tuned HEMT VCO as an active source. Noted that the measured scan angles of the 1×1 and 1×4 antennas were approximately 24◦ and the scanning range of the 1×2 antenna was 20◦. Furthermore, reflected wave due to the open end of each leaky-wave antenna element has been suppressed by the symmetric configuration of this antenna array and the antenna efficiency increases. When comparing with the measured radiation pattern of the single element antenna, we found that the 1×2 and 1×4 antenna arrays can effectively sup- press the reflected power by more than 5.5 dB and 10.5 dB, re- spectively, at 10.2 GHz. The power gain are more than 2 dB and 3.16 dB higher than the single element antenna with a measured EIRP of 18.67 dBm.

Resistance to chemotherapy is one of the major problems in treatment responses of lung cancer. This study explored the mechanism underlying the arsenic resistance of lung cancer. Four lung cancer cells with different proliferation activity were characterized for cytotoxicity, arsenic influx/efflux, and arsenic effects on intracellular glutathione and 8-hydroxy-2'-deoxyguanosine (8-OHdG) production. Our data revealed that relative proliferation potency of these cells was H1299>A549>CL3>H1355. Moreover, A549, H1299, and H1355 were markedly resistant to As(2)O(3) with IC50 approximately 100 microM, whereas CL3 was sensitive to As(2)O(3) with IC50 approximately 11.8 microM. After treatment with the respective As(2)O(3) at IC50, arsenic influx/efflux activity in CL3 was comparable to those in the other three arsenic-resistant cells. However, differences in glutathione levels and 8-OHdG production were also detected either before or after arsenic treatment, indicating that a certain degree of variation in anti-oxidative systems and/or 8-OHdG repair activity existed in these cell lines. By transfection of an aquaglyceroporin 9 (AQP9) gene, we showed that increased AQP9 expression significantly enhanced arsenic uptake and disrupted arsenic resistance of A549. The present study strongly suggests that membrane transporters responsible for arsenic uptake, such as AQP9, may play a critical role in development of arsenic resistance in human lung cancer cells.

Analysis of urinary N7-(benzo[a]pyren-6-yl)guanine (BP-6-N7Gua), a DNA adduct induced by benzo[a]pyrene, may serve as a risk-associated biomarker for exposure to polyaromatic hydrocarbons (PAHs). In this study a highly sensitive and specific analytical method, incorporating on-line sample preparation coupled with isotope-dilution liquid chromatography and tandem mass spectrometry (LC/MS/MS), was developed to quantitate this adduct in human urine. In order to achieve accurate quantitation, 15N5-labeled BP-6-N7Gua was synthesized to serve as the internal standard, and a two-step solid-phase extraction (SPE) procedure using C8 and SCX cartridges was used for sample cleanup. BP-6-7-N7Gua was analyzed using positive ion LC/MS/MS operated in multiple reaction monitoring (MRM) mode. The [M+H]+ ions at m/z 402 and 407 and the common fragment ion of [M+H]+ at m/z 252 were monitored for quantification. The recovery of this analyte after two-step SPE was 90%, and the limit of detection was 2.5 fmol/mL in 10 mL of urine. This highly specific and sensitive method for BP-6-N7Gua in urine may be applied to assess exposure to PAHs in coke-oven workers for future molecular epidemiology studies on health effects of PAHs.

ABSTRACT A new method which can enhance the scanning angle and elevate the operating frequency for active scanning leaky-wave antennas is proposed in this paper. We know that the characteristics and performance of scanning leaky-wave antennas are strongly dependent on the variation of the operating frequency within the leaky-mode region. The self-oscillating doubler without external oscillator sources provides double-frequency variation at the second-harmonic frequency instead of one-frequency variation at the fundamental frequency. Therefore, the antenna scanning range can be enhanced and the operating frequency can be elevated. The measured scanning angle of this antenna is 13°, which agrees well with the predicted 13.7°, and the data show that the frequency-scanning ability of the leaky-wave antenna using a self-oscillating doubler increases as predicted. This self-oscillating doubler design is very simple, and it not only can improve the scanning capability of the active leaky-wave antenna, but it is also very suitable for millimeter-wave active antenna design. ©1999 John Wiley & Sons, Inc. Microwave Opt Technol Lett 22: 108–111, 1999.

ABSTRACT A coplanar waveguide (CPW)-fed two-arm spiral slot antenna in applications of multi-system integration has been demonstrated in this paper. Variations of the measured impedance matching due to the turn numbers, the ground width separated between two neighboring turns and the slot width are discussed. The measured impedance bandwidth of a VSWR les 2 ranges from 1.6 to 8 GHz and covers the most of the commercial wireless communication systems, such as DCS, PCS, IMT-2000, WLAN, Bluetooth and HIPERLAN.

ABSTRACT A dual‐band monopole antenna for UHF‐band applications has been demonstrated in this work. The dual‐band characteristics are achieved using several strip monopole radiators. In addition, a small planar inverted‐F monopole antenna is connected to the ground plane. The bandwidth improvement for the antenna is obtained mainly by modifying the geometrical configuration of the strip monopoles added at the antenna and the ground plane. The measured results of the impedance‐bandwidth are about 44 MHz (458–502 MHz) and 118 MHz (701–819 MHz). © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:896–900, 2014

ABSTRACT In this study, a coplanar waveguide-fed band-selective filter and a spiral slot antenna have been designed, fabricated, and integrated for the applications of multisystem integration. The antenna module was fabricated on the same plane of the substrate, so that the circuit process and the position alignment could be simplified. The passband responses of the filter ranging below 2.6 GHz and from 5.0 to 6.0 GHz cover most of the commercial wireless communication systems. Simulated results are compared with measurements performed on the antenna module. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 2264–2267, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21915

ABSTRACT This work examines the resonant‐mode analysis of the microstrip traveling antenna (or calling the leaky‐wave antenna). Considering the traveling antenna as an open‐end structure, the antenna embodiment can be analyzed by utilizing the cavity‐mode analysis. In order to understand the resonant characteristics of the traveling antenna, we use two traditional traveling antennas with two different lengths. The corresponding relationship between the resonant modes for the short and long antennas is derived. The radiation mechanism of the antenna is also explained with aid of the equivalent magnetic current density. The antenna designers can predict the resonant modes of the traveling antenna without utilizing expensive EM simulation software. © 2013 Wiley Periodicals, Inc. Microwave Opt Technol Lett 55:2556–2562, 2013

New techniques of designing a compact coplanar-waveguide (CPW) harmonic-suppressed resonator -using the defected ground structure (DGS) resonator with floating or shorting patches are proposed in this paper. Two T-shaped slots as a bandstop resonator are etched in two ground ...

ABSTRACT The design is described of a coplanar-waveguide (CPW)-fed circularly polarized slot antenna. The slot antenna and the feeding structure are fabricated on the same plane of the substrate so that circuit process and position alignment could be simplified. By etching a longitudinal slot at a middle point of a stair-shaped slot and tuning geometrical parameters, two orthogonal electric fields with quadrature phase difference excite a circularly-polarized wave. A bandwidth of 31.2% (2.30-3.15 GHz) is achieved with an axial ratio < 3 dB and reflection coefficient < -10 dB. Details of the design procedure for the proposed antenna are described, and the results of the antenna performance are presented and discussed.

ABSTRACT A compact wideband leaky-wave antenna (LWA) with etched slot elements and tapered structure is studied. The proposed antenna is composed of an asymmetric-fed multi-section tapered short leaky-wave antenna with two embedded slots and a ground plane with etched slot elements. Base on the concept of LWA, the asymmetric-fed is utilized to excite the first higher order mode. By etching slot elements on the ground plane, the current distribution of this antenna can be influenced to compact the width of conventional LWA. In order to achieve the impedance matching, this multi-section tapered short leaky-wave antenna is embedded with two rectangular slots. This technique not only improves the impedance matching but also suppresses the back lobe. According to the measured results, the impedance bandwidth achieves about 1.30 GHz for 7-dB return loss, which covers the range from 3.30 to 4.60 GHz, and the scanning angle of the measured main beam is about 36°, which covers the range from 17° to 53°. This short LWA is only about 1.14 λ0 at 3.4 GHz, and the back lobe can be suppressed by 7.5 dB at 4.3 GHz. Due to the etched slot elements on the ground plane, the frequency of the radiation angle is shifted to lower frequency by 750 MHz, which can compact the width of LWA by more than 20%.

Novel broadband monopole antenna designs with dual-band circular polarization (CP) are presented. The proposed antenna comprised of a ground plane embedded with an inverted-L slit, which is capable of generating a resonant mode for broadband impedance-bandwidth, and excites two orthogonal E vectors with equal amplitude and 90deg phase difference (PD) for radiating left-hand circular polarization (LHCP) at 2.5 GHz and

A novel two-beam scanning active leaky-wave antenna (LWA) has been developed. This LWA with a two-terminal feeding microstrip line structure is integrated with a varactor-tuned X-band high-electron mobility transistor (HEMT) voltage-controlled oscillator (VCO). The signal of the VCO is injected via a T-divider into the radiating element. To excite the first higher order mode, the designed antenna is fed asymmetrically

ABSTRACT In this study, the resonant analysis and modeling of the microstrip-fed stepped-impedance (SI) slot antenna are presented by utilizing the transmission-line and lumped-element circuit topologies. This study analyzes the SI-slot antenna and systematically summarizes its frequency response characteristics, such as the resonance condition, spurious response, and equivalent circuit. Design formulas with respect to the impedance ratio of the SI slot antenna were analytically derived. The antenna designers can predict the resonant modes of the SI slot antenna without utilizing expensive EM- simulation software.

This paper describes a two-directional linear scanned design by integrating a short leaky-wave antenna (LWA) with aperture-coupled patch antenna arrays. This architecture proposes a technique not only having the advantage of suppressing the back-lobe due to the reflected wave in the short LWA but also producing two separate linearly scanned beams, each of them radiating in a different region of