Jaehoon Choi

Bio: Jaehoon Choi is an academic researcher from Hanyang University. The author has contributed to research in topics: Microstrip antenna & Monopole antenna. The author has an hindex of 10, co-authored 13 publications receiving 759 citations.

A small wideband microstrip-fed monopole antenna

Abstract: A small microstrip-fed monopole antenna, which consists of a rectangular patch and a truncated ground plane, is presented for ultra wideband application. The proposed antenna is designed to operate over 3.1 to 11GHz for S/sub 11/<-10dB. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest.

Wideband microstrip-fed monopole antenna having frequency band-notch function

Abstract: A novel and compact ultra-wideband (UWB) microstrip-fed monopole antenna having frequency band notch function is presented. To increase the impedance bandwidth of an antenna, a narrow slit is used. By inserting a modified inverted U-slot on the proposed antenna, the frequency band notch characteristic is obtained. The designed antenna satisfies the voltage standing wave ratio requirement of less than 2.0 in the frequency band between 3 and 11 GHz while showing the band rejection performance in the frequency band of 5.0 to 5.9 GHz.

Wideband CPW-fed monopole antenna with parasitic elements and slots

Abstract: A novel compact and wideband coplanar waveguide(CPW)-fed monopole antenna is proposed To increase the impedance bandwidth, two parasitic elements and three slots are added, which structures are optimised by a parametric analysis The antenna operates over 31 to 11 GHz for the return loss of less than −10 dB Radiation patterns also show very well omnidirectional performance of the proposed antenna

Compact ultra-wideband printed antenna with band-rejection characteristic

Abstract: A novel and compact ultra-wideband printed antenna with band-rejection characteristic is proposed. By cutting an L-shaped notch on the radiating patch, the impedance bandwidth of the proposed antenna can be enhanced. In addition, a C-shaped slot is introduced to obtain the band-rejection operation of the antenna. The antenna, with compact size of 15.5×21 mm including the ground plane, operates over 3.08–10.97 GHz and has the rejected band from 5.03 to 5.91 GHz.

Design of a planar inverted-F Antenna with very wide impedance bandwidth

Abstract: This letter presents a novel wideband planar inverted F-antenna, which covers GSM850/DCS1800/DCS1900/ IMT2000/WLAN/DMB services at the same time. The proposed antenna consists of a main patch with a pair of slant slits and L-shaped patch and occupies a total volume of 15times44times8mm3. The triple frequency bands are obtained by changing the length and width of a slant slit 1 on the main patch. A very wide impedance bandwidth characteristic is achieved by optimizing not only the length and height of a L-shaped patch between the main patch and ground plane but also the length and width of a pair of slits on the main patch which is excited by the modified coplanar waveguide-feed. Good broadside radiation patterns are achieved for all six-frequency bands of interest

Small Printed Ultrawideband Antenna With Reduced Ground Plane Effect

Abstract: A small printed antenna is described with a reduced ground-plane effect for ultrawideband (UWB) applications. The radiator and ground plane of the antenna are etched onto a piece of printed circuit board (PCB) with an overall size of 25mmtimes25 mmtimes1.5 mm. A notch is cut from the radiator while a strip is asymmetrically attached to the radiator. The simulation and measurement show that the miniaturized antenna achieves a broad operating bandwidth of 2.9-11.6 GHz for a 10-dB return loss. In particular, the ground-plane effect on impedance performance is greatly reduced by cutting the notch from the radiator because the electric currents on the ground plane are significantly suppressed at the lower edge operating frequencies. The antenna features three-dimensional omni-directional radiation with high radiation efficiency of 79%-95% across the UWB bandwidth. In addition, a parametric study of the geometric and electric parameters of the proposed antenna will be able to provide antenna engineers with more design information

Planar Ultrawideband Antennas With Multiple Notched Bands Based on Etched Slots on the Patch and/or Split Ring Resonators on the Feed Line

Abstract: Three types of ultrawideband (UWB) antennas with triple notched bands are proposed and investigated for UWB communication applications. The proposed antennas consist of a planar circular patch monopole UWB antenna and multiple etched slots on the patch and/or split ring resonators (SRRs) coupled to the feed line. Good agreement is achieved between the simulated and measured results. These techniques are significant for designing UWB antennas with multiple narrow frequency notched bands or for designing multiband antennas.

Study of CPW-fed circular disc monopole antenna for ultra wideband applications

Abstract: The paper presents a study of coplanar waveguide (CPW) fed circular disc monopole antenna for ultra-wideband (UWB) applications. A circular disc monopole printed on a dielectric substrate and fed by a 50 /spl Omega/ CPW on the same layer can yield an ultra-wide -10 dB return loss bandwidth with satisfactory radiation patterns. The performance and characteristics of the antenna are investigated in order to understand its operation. Good agreement has been obtained between the simulation and experiment.

Antennas for Portable Devices

Abstract: Foreword. Acknowledgements. List of Contributors. 1 Introduction (Zhi Ning Chen). References. 2 Handset Antennas (Brian S. Collins). 2.1 Introduction. 2.2 Performance Requirements. 2.3 Electrically Small Antennas. 2.4 Classes of Handset Antennas. 2.5 The Quest for Efficiency and Extended Bandwidth. 2.5.1 Handset Geometries. 2.5.2 Antenna Position in the Handset. 2.5.3 The Effect of the User. 2.5.4 Antenna Volume. 2.5.5 Impedance Behavior of a Typical Antenna in the Low Band. 2.5.6 Fields and Currents on Handsets. 2.5.7 Managing the Length-Bandwidth Relationship. 2.5.8 The Effect on RF Efficiency of Other Components of the Handset. 2.5.9 Specific Absorption Rate. 2.5.10 Hearing Aid Compliance. 2.5.11 Economic Considerations. 2.6 Practical Design. 2.6.1 Simulations. 2.6.2 Materials and Construction. 2.6.3 Recycling. 2.6.4 Building the Prototype. 2.6.5 Measurement. 2.6.6 Design Optimization. 2.7 Starting Points for Design and Optimization. 2.7.1 External Antennas. 2.7.2 Balanced Antennas. 2.7.3 Antennas for Other Services. 2.7.4 Dual-Antenna Interference Cancellation. 2.7.5 Multiple Input, Multiple Output. 2.7.6 Antennas for Lower-Frequency Bands - TV and Radio Services. 2.8 The RF Performance of Typical Handsets. 2.9 Conclusion. References. 3 RFID Tag Antennas (Xianming Qing and Zhi Ning Chen). 3.1 Introduction. 3.2 RFID Fundamentals. 3.2.1 RFID System Configuration. 3.2.2 Classification of RFID Systems. 3.2.3 Principles of Operation. 3.2.4 Frequencies, Regulations and Standardization. 3.3 Design Considerations for RFID Tag Antennas. 3.3.1 Near-field RFID Tag Antennas. 3.3.2 Far-field RFID Tag Antennas. 3.4 Effect of Environment on RFID Tag Antennas. 3.4.1 Near-field Tags. 3.4.2 Far-field Tags. 3.4.3 Case Study. 3.5 Summary. References. 4 Laptop Antenna Design and Evaluation (Duixian Liu and Brian Gaucher). 4.1 Introduction. 4.2 Laptop-Related Antenna Issues. 4.2.1 Typical Laptop Display Construction. 4.2.2 Possible Antennas for Laptop Applications. 4.2.3 Mechanical and Industrial Design Restrictions. 4.2.4 LCD Surface Treatment in Simulations. 4.2.5 Antenna Orientation in Display. 4.2.6 The Difference between Laptop and Cellphone Antennas. 4.2.7 Antenna Location Evaluations. 4.3 Antenna Design Methodology. 4.3.1 Modeling. 4.3.2 Cut-and-Try. 4.3.3 Measurements. 4.4 PC Card Antenna Performance and Evaluation. 4.5 Link Budget Model. 4.6 An INF Antenna Implementation. 4.7 Integrated and PC Card Solutions Comparison. 4.8 Dualband Examples. 4.8.1 An Inverted-F Antenna with Coupled Elements. 4.8.2 A Dualband PCB Antenna with Coupled Floating Elements. 4.8.3 A Loop Related Dualband Antenna. 4.9 Remarks on WLAN Antenna Design and Evaluations. 4.10 Antennas for Wireless Wide Area Network Applications. 4.10.1 INF Antenna Height Effects on Bandwidth. 4.10.2 A WWAN Dualband Example. 4.11 Ultra-Wide Band Antennas. 4.11.1 Description of the UWB Antenna. 4.11.2 UWB Antenna Measurement Results. References. 5 Antenna Issues in Microwave Thermal Therapies (Koichi Ito and Kazuyuki Saito). 5.1 Microwave Thermal Therapies. 5.1.1 Introduction. 5.1.2 Classification by Therapeutic Temperature. 5.1.3 Heating Schemes. 5.2 Interstitial Microwave Hyperthermia. 5.2.1 Introduction and Requirements. 5.2.2 Coaxial-Slot Antenna. 5.2.3 Numerical Calculation. 5.2.4 Performance of the Coaxial-Slot Antenna. 5.2.5 Temperature Distributions Around the Antennas. 5.3 Clinical Trials. 5.3.1 Equipment. 5.3.2 Treatment by Use of a Single Antenna. 5.3.3 Treatment by Use of an Array Applicator. 5.3.4 Results of the Treatment. 5.4 Other Applications. 5.4.1 Treatment of Brain Tumors. 5.4.2 Intracavitary Microwave Hyperthermia for Bile Duct Carcinoma. 5.5 Summary. References. 6 Antennas for Wearable Devices (Akram Alomainy, Yang Hao and Frank Pasveer). 6.1 Introduction. 6.1.1 Wireless Body Area Networks. 6.1.2 Antenna Design Requirements for Wireless BAN/PAN. 6.2 Modelling and Characterization of Wearable Antennas. 6.2.1 Wearable Antennas for BANs/PANs. 6.2.2 UWB Wearable Antennas. 6.3 WBAN Radio Channel Characterization and Effect of Wearable Antennas. 6.3.1 Radio Propagation Measurement for WBANs. 6.3.2 Propagation Channel Characteristics. 6.4 Case Study: A Compact Wearable Antenna for Healthcare Sensors. 6.4.1 Application Requirements. 6.4.2 Theoretical Antenna Considerations. 6.4.3 Sensor Antenna Modelling and Characterization. 6.4.4 Propagation Channel Characterization. 6.5 Summary. References. 7 Antennas for UWB Applications (Zhi Ning Chen and Terence S.P. See). 7.1 UWB Wireless Systems. 7.2 Challenges in UWB Antenna Design. 7.3 State-of-the-Art Solutions. 7.3.1 Frequency-Independent Designs. 7.3.2 Planar Broadband Designs. 7.3.3 Crossed and Rolled Planar Broadband Designs. 7.3.4 Planar Printed PCB Designs. 7.3.5 Planar Antipodal Vivaldi Designs. 7.4 Case Study. 7.4.1 Small Printed Antenna with Reduced Ground-Plane Effect. 7.4.2 Wireless USB. 7.5 Summary. References. Index.

Small Square Monopole Antenna With Inverted T-Shaped Notch in the Ground Plane for UWB Application

Abstract: In this letter, we present a novel printed monopole antenna for ultrawideband (UWB) applications. The proposed antenna consists of a square radiating patch with two rectangular slots and a ground plane with inverted T-shaped notch, which provides a wide usable fractional bandwidth of more than 120% (3.1212.73 GHz). The proposed antenna is simple and small in size. Simulated and experimental results obtained for this antenna show that it exhibits good radiation behavior within the UWB frequency range.