Cheon-Hee Lee

Design of dualband metamaterial bandpass filter using zeroth order resonance

This paper proposes the design method based on the composite right/left-handed (CRLH) structure to miniaturize and generate the dual-band characteristic. For realization, we used the zero-th order resonance point of the CRLH and the simple theory of Inverter. The proposed technique is validated by the performance predictions and experiments, and it is found out that the suggested method enables the huge size reduction from the conventional filters such as the parallel coupled type which was designed following the half-wavelength resonance.

A Flexible Monopole Antenna with Band-notch Function for UWB Systems

A flexible monopole antenna for UWB systems is proposed. The proposed antenna has good performance over the entire UWB bandwidth, and it enhanced the impedance bandwidth by using the stepped CPW feed line. It can be easily mounted on conformal shape, because it is fabricated on PET film having the flexible characteristic. It has a band-notch function of 5 GHz WLAN band using two slits. From the results, it is observed that the proposed antenna has the similar radiation patterns and the return loss in comparison with the planar type monopole antenna, when it is rolled.

A CPW-fed flexible monopole antenna for UWB systems

A CPW-fed flexible monopole antenna on PET film for UWB systems is proposed. The proposed antenna has good performance over the entire UWB bandwidth, and it enhanced the impedance bandwidth by using the stepped CPW feed line. It can be easily mounted on conformal shape, because it is fabricated on PET film having the flexible characteristic. From the results, it is observed that the proposed antenna has the similar radiation patterns and the return loss in comparison with the planar type monopole antenna, when it is rolled.

A CPW-fed polarization diversity antenna for UWB systems

A CPW-fed polarization diversity monopole antenna on flexible PET film for UWB systems is proposed. The antenna consists of two heptagonal monopoles orthogonally and symmetrically printed on the two sides of the extended Vshape ground plane. It covers the entire UWB bandwidth from 3.1 GHz to 10.6 GHz and shows a good port isolation under -20 dB over the entire UWB bandwidth. Also, it has a band-notch function of 5 GHz WLAN band. It can be easily mounted on conformal shape, because it is fabricated on PET film having the flexible characteristic. From the results, it is observed that the proposed antenna can provide the polarization diversity for UWB communications.

A Flexible UWB Antenna Attachable to Various Kinds of Materials

A flexible monopole antenna fabricated on PET film for UWB systems is proposed and the effects of the various kinds of the attached materials is analyzed. The proposed antenna has good performance over the entire UWB bandwidth, and it can be mounted on various kinds of conformal materials meeting the UWB bandwidth by using the stepped CPW feed line and the beveled ground plane. From the results, it is observed that the proposed antenna has the similar radiation patterns and the return loss in comparison with the planar type monopole antenna, when it is rolled.

A compact polarization diversity antenna for UWB systems

Compact polarization diversity antenna fabricated on different substrates for UWB systems is proposed. To obtain the wide bandwidth, the tapered CPW line is used and extended ground plane of the slot antenna makes the proposed antenna size smaller. The different substrates with different dielectric constants are also effective in enhancing the isolation between the feed ports of the two antennas. Consequently, the proposed antenna meets the frequency band 7.2-9.2 GHz and shows the good isolation performance (S21les20 dB) and the stable radiation patterns over the upper UWB bandwidth. With the compact dimension characteristic, the proposed antenna can be used in the small types of UWB device used in indoor data transmission.

Low band UWB BPF using CRLH-TL metamaterial structure

The design of a new UWB lower-half bandpass filter is proposed, which is based upon the microstrip Composite Right-and Left-Handed Transmission-line(CRLH-TL) metamaterial. Particularly, the interdigital coupled(IDC) lines of the CRLH geometry are proposed to be separated by inserting open stubs to meet the specs on the passband. Also, there is another pair of stubs to complete the design in a limited space. The measurement is shown to be acceptable and agreeable with the circuit and Electromagnetic field simulations

A small-sized automobile LTE multi-band MIMO antenna

This paper deals with an effective method to maximize the characteristics of a MIMO antenna system for cars. This stems from the improvement of isolation between the two radiators. A metamaterial kind of decoupling device which is a modified SRR curbs the unwanted interaction between the MIMO elements. New flat dual-band monopoles with the interference-reduction device for the MIMO system are suggested and the numerically experimented results of the cases without and with the proposed structure are compared. These show how good isolation level is obtained. It is certain that the entire structure is adoptable to the placement on the car surface.

A low profile, wideband and high gain beam-steering antenna for 5G mobile communication

A low profile, wideband and high gain Substrate Integrated Waveguide (SIW) Transmission Line (TL) Butler Matrix (BM) beamforming network (BFN) for beamforming and beam-steering applications at 28 GHz (5G) is presented in this paper. Four distinct beams steering between −50° to 50° with sidelobe and return-loss level below −10 dB are generated by connecting the proposed BFN to microstrip antennas forming a phased array antenna. The simulated and measured results are shown and discussed.