Joonho Byun

Interaction Between Internal Antenna and External Antenna of Mobile Phone and Hand Effect

In this paper, we begin by presenting a multiband antenna for mobile phone applications operating in GSM, DCS, PCS, UMTS, Bluetooth, and LTE bands. The antenna platform includes the ground plane, the battery, the camera, and other paraphernalia that the mobile phone environment typically comprises. Results show that the platform has a significant effect on the performance of the antenna, both in terms of its bandwidth and the number of its resonance frequencies. In addition, metal rings, frequently used in a mobile phone for mechanical reasons, can also have a significant influence on the performance of the antenna in the phone. Equivalent circuits and current distributions have been derived with the objective of investigating the effects of the metal ring that embrace the mobile phone. We investigate ways in which we can modify the ring so as to restore the desired performance of the antenna, which has been previously designed to operate in the phone environment but without the presence of the ring. We show how we can control the resonances of the ring by using capacitance loading and lower its Q by loading the ring resistively at a number of different strategic locations along the ring.

Compact UWB Antenna With I-Shaped Band-Notch Parasitic Element for Laptop Applications

A compact ultrawideband (UWB) antenna with a band-notch function is proposed for laptop applications. The band-notch function is realized by a half-wavelength parasitic element printed on the rear side of the substrate. The impedance bandwidth (VSWR < 2) of the antenna is 3.1 ~ 11.4 GHz (114%) with a notched frequency from 5.05 to 5.90 GHz. The antenna has a fairly good omnidirectional pattern, and the average gain is -3.0 ~ -1.2 dBi over the UWB frequency band except for the notched frequency band. The performance of the proposed antenna is confirmed by simulation and measurement results.

The compact quad-band mobile handset antenna for the LTE700 MIMO application

Fig. 3 shows the measured and simulated return loss of the proposed antenna. The lower band is tuned at about 770 MHz and has a bandwidth (1:3 VSWR) of 70 MHz (Antenna 1:735–810MHz, Antenna 2:740–800MHz), which satisfies the operating bandwidth of the LTE band class 13 (746–787 MHz). The GPS band has a bandwidth (1:3 VSWR) of 200 MHz (1410–1610MHz), which satisfies the operating bandwidth of the GPS at L1 band (1565∼1585MHz). The PCS and UMTS band has a bandwidth (1:3 VSWR) of 400MHz (1790–2190) PCS and UMTS band (1810–2170MHz). The obtained bandwidths meet the bandwidth requirement of the LTE band class 13, GPS at L1 band, PCS and UMTS mobile handset systems. The average gain was measured in the Reverberation 3D chamber [2] and the corresponding radiation patterns are shown in Fig. 4. Table I. shows the average gain data of the whole frequency bands and table II. shows the important factors for LTE700 MIMO performance. When the suspended line is applied to the proposed antennas, those have better performance compared to antennas excluding suspended line. Suspended line between antennas is able to operate like a band stop filter. This is an important factor to maintain a high isolation. The proposed antennas connected by suspended line can easily be applied to commercial RF devices such as a USB dongle and an express card for MIMO systems. The demands of MIMO system will significantly increase in the near future. Proposed structure of the antennas and suspended line is very promising.

DVB-H Antenna Design Using Folder-Type Chassis and Coupling Element on a Ferrite

This letter presents a new design concept of the digital video broadcast-handheld (DVB-H) antenna using the folder-type chassis and coupling element on a ferrite. By utilizing the chassis as a radiator in conjunction with a compact coupling element on a ferrite, the antenna achieves DVB-H operation without an additional matching circuit. The measured result shows the wide bandwidth of 250 MHz (VSWR< 6) with sufficient peak gains over -5 dBi in the DVB-H band.

Generation of Rayleigh/Rician Fading Channels With Variable RMS Delay by Changing Boundary Conditions of the Reverberation Chamber

This letter presents the properties of the generated Rayleigh/Rician fading channels in the reverberation chamber (RC) experimentally. Radio propagation channels that undergo multipath fading phenomena can be characterized by power delay profiles (PDPs), delay spreads, and statistical distributions of the received power. The RC under the conventional configuration for electromagnetic compatibility/electromagnetic interference (EMC/EMI) evaluations has Rayleigh distribution because there are no direct paths between the TX and RX antennas. Most of the transmitted signals arrive at the RX part through multiple reflection paths. By changing the boundary conditions and the position of the TX antenna, Rayleigh/Rician fading channels with variable root-mean-square (RMS) delay spread can be generated in the RC considering K-factor simultaneously.

Internal dual-band WLAN antenna for laptop applications

This paper presents a dual-band (2.4 GHz, 5.2/5.8 GHz) WLAN antenna for laptop applications. The proposed antenna consists of the folded-dipole structure operated at higher band and two arms operated at lower band. The radiation pattern of a proposed antenna is orthogonal to that of a conventional monopole at all operating frequency bands.

Multi-band diversity antenna for mobile handset applications

A diversity antenna for a tri-band application is proposed and designed. The proposed diversity antenna consists of two wideband planar inverted-F antennas (PIFAs) and a suspended line between two PIFAs. The measured results show that the proposed antenna has a wide impedance bandwidth (37%) enough to serve a triple band (PCS, UMTS and WiMAX), a high radiation efficiency (> 50%), and a low correlation coefficient (< 0.2).

The compact Quad-band PCB embedded antenna for mobile handsets

This paper presents a novel PCB embedded antenna for GSM900/DCS1800/PCS1900/UMTS2100 band operations. The proposed antenna is composed of conventional loop and PIFA antenna. This antenna occupies a compact area, 30times15 mm2 only and does not need the thickness. In order to reduce the effective antenna length for the resonance of the GSM900 band, the electrical coupling between the ground of PCB and antenna radiator is used.

Designing a quad-band antenna for mobile phone applications including metal ring and hand effects

The objective of this paper is to present a quad-band antenna for handset application includes the effects of a metallic ring and a hand. We show that it is necessary to co-design the antenna and the ring together, since the metal ring has a significant influence on the performance of the antenna. The effect of the hand on the efficiency of the composite antenna and metal ring is investigated and it is shown that the radiation efficiency of the phone degrades rather significantly when the phone is gripped by the hand.

Enhanced isolation between donor antenna and coverage antenna for indoor WCDMA repeater systems

This paper presents a structure of the Frequency Selective Surface (FSS) to improve the isolation between donor antenna and coverage antenna for indoor WCDMA repeater systems. The repeater system has two linearly polarized antennas backed with the reflectors. The proposed FSS is embedded into reflectors aligned with the cross-polarization of each antenna. The isolation with the FSS is enhanced overall more than 6 dB at WCDMA band, compared to that without the FSS.