Seokjin Hong

Design of an Internal Multiresonant Monopole Antenna for GSM900/DCS1800/US-PCS/S-DMB Operation

A design is proposed of a multiresonant monopole antenna for a personal wireless communication handset. Multiresonant operation is achieved through the use of a bent tuning stub, a shorting strip line, a U-shaped slit and the addition of a narrow resonant slit to the main radiator. The first resonant frequency is determined by the main radiator of the proposed antenna, and the second resonant frequency is controlled by the length of the bent tuning stub. The third resonant frequency is generated by adding a narrow resonant slit to the perimeter of the main radiator. The three resonant frequencies of the designed antenna can be independently controlled by tuning the length of the individual elements of the proposed antenna. The measurement shows the intended four wireless communication services: global system for mobile communication (GSM900), digital communication system (DCS1800), US-personal communication system (US-PCS), and satellite-digital multimedia broadcasting (S-DMB). The proposed antenna is small enough to be built into a practical wireless mobile handset. The parameters determining the antennas multiresonant characteristics are analyzed, and experimental results of the constructed prototype are presented and discussed.

Design of UWB Diversity Antenna for PDA Applications

Two elements diversity planar antenna for a multiple-input multiple-output application is proposed. By adopting two Y-shaped radiators, the antenna provides wideband impedance matching characteristic over the desired frequency band. To reduce the mutual coupling between two radiating elements, three stubs are inserted in the ground plane. Good impedance matching and improved isolation characteristics are observed. The measured impedance bandwidth of the proposed antenna ranges from 2.27 GHz to 10.2 GHz for return loss less than 10 dB. Parametric analysis has been conducted to investigate the effect of radiator length and insertion of stubs on the impedance bandwidth and isolation characteristics.

A Compact Ultrawideband Monopole Antenna for Wireless Communication Application

An internal ultrawideband monopole antenna for use in the portable wireless communication applications is presented. The proposed antenna had compact dimensions of 12 mm ×16 mm × 4.5 mm. It consisted of a radiating patch, a matching stub, and a ground plane. The designed antenna was fabricated with a case and had a wide bandwidth of more than 8.7 GHz (2.3-11 GHz) for a return loss of less than 10 dB. With this ultrawideband capability, the antenna could cover the wireless-broadband (2.3-2.39 GHz), Bluetooth (2.4-2.4835 GHz), S-DMB (2.605-2.655 GHz), and UWB (3.1-10.6 GHz) bands. The performances of the proposed antenna as installed on a laptop computer was investigated and discussed.

Design of CP Antenna with a Fenced Ground for a Handheld RFID Reader

A design of circular polarized(CP) microstrip antenna with a fenced ground is proposed and the equivalent circuit is derived. The antenna consists of a square radiating patch with a pair of truncated corners, a bottom ground and a fenced ground. From conducted experiments, a patch size reduction using the metal fence as large as 25 % from the conventional patch structure, has been obtained. The input admittance of the extracted equivalent circuit is shown to agree with that of the measurement. And the design parameters and performance of the proposed antenna are examined by analyzing the fields and circuit behaviors.

The Design of an UWB Antenna with Notch Characteristic

Four types of novel and compact ultra-wideband (UWB) microstrip-fed monopole antennas having frequency band-stop function are presented. To generate the band-stop perfor- mance, modifled planar monopoles with inverted U-slot, U-slot, small strip bar and ‚=4 C-shaped slot are used. The designed antennas satisfy the i10dB return loss requirement in the frequency band between 3 and 11GHz, while showing the band-stop characteristic in the frequency band of 5.0 to 5.9GHz. DOI: 10.2529/PIERS061007113522

Design of a Multiband Antenna using a Planner Inverted-F Structure

In this paper, a planar inverted-F antenna with wideband characteristic is proposed for GSM850/DCS1800/DCS1900/EMT200/WLAN/DMB services at the same time. The proposed antenna is composed of a main patch with a pair of slant slits and L-shaped patch and has total volume of 15 times 45 times 8 mm3. To achieve triple band operation, the length and width of a slant slit 1 on the main patch are optimized. To increase the impedance bandwidth of an antenna, the length and width of two slant slits on the main patch, which is excited by the modified CPW-fed, are changed. The length and height of an L-shaped patch between the main patch and ground plane are optimized. Measured results show that the proposed antenna provides enough bandwidth to cover six bands for return loss than -10 dB. Good broadside radiation patterns are also achieved for all six bands of interest. Measured results are presented and discussed in detail.

A Compact Printed Antenna with Band-stop Characteristic for UWB Application

A Compact antenna with a band-stop characteristic for ultra-wideband application is proposed. To increase the impedance bandwidth of the proposed antenna, a tapered ground and circular slot are used. By attaching an inverted Y-shaped open-circuited stub in the circular ring, the band-stop characteristic is obtained. The designed antenna satisfles the voltage standing wave ratio requirement of less than 2.0 in the frequency between 3.12GHz and 10.73GHz while showing the band stop performance in the frequency band of 5.15GHz to 5.78GHz. This antenna shows an omnidirectional radiation pattern similar to that of a monopole antenna. DOI: 10.2529/PIERS060825233410

Design of a band-notched wideband antenna for UWB applications

A simple and compact microstrip-fed ultrawide-band (UWB) printed monopole antenna with band-notch characteristic is proposed. The antenna is composed of two monopoles of the same size and a small strip bar which leads to the desired high attenuation at the notch frequency. Details of the antenna design are presented and discussed. The band-notch mechanism and current distribution of the antenna are examined. Finally, the frequency-domain characteristics are analyzed to evaluate the antenna performance for UWB applications

Design of an ultra-wideband internal antenna using symmetrical radiators for mobile application

The proposed internal antenna for UWB mobile application is presented. The wideband characteristic is obtained by using the two symmetrical radiators on top and bottom layer with a L-shaped ground. The antenna has compact in size and can be easily integrated on PCB. Since the manufactured antenna has good impedance bandwidth and approximately omni-directional radiation patterns, the proposed antenna can be easily adopted to an UWB mobile terminals.

Design of a novel modified spiral antenna for UWB application

In this paper, a compact microstrip-fed modified spiral antenna for UWB band is proposed. To widen the operating bandwidth and reduce the size, two elements with spiral structure are adopted. By controlling the number of turns, width of the spiral element, and distance between the two spiral elements, the broadband impedance characteristic is achieved.