Ka Ming Mak

The University of Hong Kong, Hong Kong, Hong Kong

Are you Ka Ming Mak?

Claim your profile

Publications (12)9.63 Total impact

  • Ka Ming Mak, Xia Gao, Hau Wah Lai
    [Show abstract] [Hide abstract]
    ABSTRACT: A broadband low profile dual polarized patch antenna for fourth generation long term evolution (4G LTE) is presented in this communication. By employing two wideband feeding mechanisms for the two input ports, a dual polarized patch antenna element with the characteristics of high input port isolation and wide impedance bandwidth is successfully designed. A wide meandering probe (M-probe) and a pair of twin-L-probes are proposed to feed a patch for dual polarization. The proposed design with a wideband balun has impedance bandwidths of over 47% at the two input ports as well as over 37 dB isolation within the entire operating band. Over 8 dBi gain can be achieved at the two ports.
    IEEE Transactions on Antennas and Propagation 11/2014; 62(11):5861-5865. DOI:10.1109/TAP.2014.2347411 · 2.46 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: A circularly polarized patch antenna for future fifth-generation mobile phones is presented in this paper. Miniaturization and beamwidth enhancement of a patch antenna are the two main areas to be discussed. By folding the edge of the radiating patch with loading slots, the size of the patch antenna is 44.8% smaller than a conventional half wavelength patch, which allows it to be accommodated inside handsets easily. Wide beamwidth is obtained by surrounding the patch with a dielectric substrate and supporting the antenna by a metallic block. A measured half power beamwidth of 124° is achieved. The impedance bandwidth of the antenna is over 10%, and the 3-dB axial ratio bandwidth is 3.05%. The proposed antenna covers a wide elevation angle and complete azimuth range. A parametric study of the effect of the metallic block and the surrounding dielectric substrate on the gain at a low elevation angle and the axial ratio of the proposed antenna are presented.
    01/2014; 2:1521-1529. DOI:10.1109/ACCESS.2014.2382111
  • Hau Wah Lai, Ka Ming Mak, Kwai Man Luk
    [Show abstract] [Hide abstract]
    ABSTRACT: A new type of cross slot antenna with very low back radiation is proposed in this paper. The proposed antenna has a very low back radiation, which is below -27dB at its center frequency. The antenna is relatively small size, including very low profile and small projection area. Its structure is also very simple and it is very easy to design. The antenna is operated at 5.8GHz, which is the ISM band (5.725-5.875 GHz, which is around 2.6%). Its potential applications include 5.8 GHz Wi-Fi, On-body communication or medical applications.
    2013 IEEE MTT-S International Microwave Workshop Series on RF and Wireless Technologies for Biomedical and Healthcare Applications (IMWS-BIO); 12/2013
  • [Show abstract] [Hide abstract]
    ABSTRACT: Two new printed circuit board types double‐folded inverted‐L antennas (DFILAs), which are the horizontal printed DFILA and the vertical printed DFILA, have been proposed.By taking advantage of the printed circuit technologies, the manufacturing processes of the DFILAs can be simplified. The proposed antennas are low profile, lightweight, and simple in structure. Both antennas perform right‐hand circular polarization with center frequency of 2.4 GHz. Both antennas have impedance bandwidths of over 7% (S11 Document Type: Research Article DOI: http://dx.doi.org/10.1002/mop.27181 Affiliations: 1: National Laboratory of Radar Signal Processing, Xidian University, Xi'an 710071, China 2: State Key Laboratory of Millimeter waves (HK), City University of Hong Kong SAR, China Publication date: December 1, 2012 $(document).ready(function() { var shortdescription = $(".originaldescription").text().replace(/\\&/g, '&').replace(/\\, '<').replace(/\\>/g, '>').replace(/\\t/g, ' ').replace(/\\n/g, ''); if (shortdescription.length > 350){ shortdescription = "" + shortdescription.substring(0,250) + "... more"; } $(".descriptionitem").prepend(shortdescription); $(".shortdescription a").click(function() { $(".shortdescription").hide(); $(".originaldescription").slideDown(); return false; }); }); Related content In this: publication By this: publisher By this author: Wang, Song ; Mak, Ka Ming ; Lai, Hau Wah ; So, Kwok Kan ; Xue, Quan ; Liao, Guisheng GA_googleFillSlot("Horizontal_banner_bottom");
    Microwave and Optical Technology Letters 12/2012; 54(12). DOI:10.1002/mop.27181 · 0.62 Impact Factor
  • Hau Wah Lai, Ka Ming Mak, Kwai Man Luk
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper presented a small wideband patch antenna with a modified half U-slot and a shorting pin. This small patch antenna can achieve an impedance bandwidth of around 40% (S11<; -10dB) by introducing a modified U-slot and a shorting pin. The antenna size is electrically small, which are 0.012λ02 (240mm2). This small antenna has a very stable radiation pattern across its operating bandwidth, and has a peak gain of 2dBi.
    2012 IEEE International Workshop on Electromagnetics; Applications and Student Innovation (iWEM); 08/2012
  • [Show abstract] [Hide abstract]
    ABSTRACT: The general method of using U-slots to design dual- and triple-band patch antennas is described. In this approach, one starts with a broadband patch antenna, which can consist of one or more patches. When a U-slot is cut in one of the patches, a notch is introduced into the matching band, and the antenna becomes a dual-band antenna. If another U-slot is cut in the same patch or in another patch, a triple-band antenna results. This method is applied to the L-probe-fed patch, the M-probe-fed patch, as well as the coaxially fed and aperture-coupled stacked patches. It is found that the patterns and gains of the dual-and triple-band antennas are similar to those of the original broadband antenna. Because the band notches introduced by the U-slots occur within the bandwidth of the antenna without slots, this method is suitable when the frequency ratios of the adjacent bands are small, usually less than 1.5.
    IEEE Antennas and Propagation Magazine 07/2011; 53(3-53):60 - 74. DOI:10.1109/MAP.2011.6028422 · 1.15 Impact Factor
  • Kai Fong Lee, Kwai Man Luk, Ka Ming Mak
    [Show abstract] [Hide abstract]
    ABSTRACT: The technique of using U-slots to design dual/triple band patch antennas is applied to patch antennas fed by meandering (M) probes. It is found that the advantage of the M-probe, namely, low cross polarization, is preserved by the use of pairs of face-to-face U-slots. © 2010 Wiley Periodicals, Inc. Microwave Opt Technol Lett 52: 1498–1504, 2010; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.25245
    Microwave and Optical Technology Letters 07/2010; 52(7):1498 - 1504. DOI:10.1002/mop.25245 · 0.62 Impact Factor
  • Ka Ming Mak, Kwai Man Luk
    [Show abstract] [Hide abstract]
    ABSTRACT: A novel circularly polarized (CP) antenna with wide angular coverage is presented. The proposed antenna is formed by two bowtie patch antennas and two electric dipoles. It can achieve an impedance bandwidth (SWR < 1.6) of 41% and a 3-dB axial ratio bandwidth of 33%. For this design, very stable and symmetrical radiation patterns are obtained. In the axial ratio passband, the 3-dB beamwidth is 85<sup>deg</sup>plusmn2<sup>deg</sup> with a gain of 6.3 dBi plusmn0.3 dBi. The cross polarization is lower than -15 dB over a wide range of angles. For the entire half-power beamwidth, the axial ratio can be kept below 3 dB.
    IEEE Transactions on Antennas and Propagation 11/2009; 57(10-57):3309 - 3312. DOI:10.1109/TAP.2009.2029370 · 2.46 Impact Factor
  • K.M. Mak, K.M. Luk
    [Show abstract] [Hide abstract]
    ABSTRACT: A novel circular-polarized antenna composed of bowtie patches, cross dipole and a power combiner is presented. Two air microstrip lines are utilized to feed the bowtie patches orthogonally. A 90-degree phase shift Wilkinson power divider is placed underneath the ground and connected to the feeds to generate circular polarization. The antenna attains an impedance bandwidth of 40.2% for return loss better than -15 dB and 3-dB axial ratio bandwidth of 29% (from 1.62 to 2.17 GHz). Very Stable and symmetric radiation patterns with low cross polarization level have been obtained over the operating frequency range. The 3-dB axial ratio beamwidth is about 90deg and the gain of the antenna is about 6.3 dBi with small variation.
    Antennas and Propagation Society International Symposium, 2007 IEEE; 07/2007
  • Hang Wong, Ka‐Ming Mak, Kwai‐Man Luk
    [Show abstract] [Hide abstract]
    ABSTRACT: A new wideband antenna employing a shorted bowtie patch for exciting a slot-type radiation is presented. Unlike a conventional directional slot antenna, which generally is placed 1/4-wavelength above a ground reflector, the height of the proposed antenna is 1/10-wavelength but a directional radiation can be achieved. The impedance bandwidth is 64% (SWR ≤ 2) from frequency of 2.07 to 4.02 GHz. The antenna does not only have a wideband feature but also has several attractive electrical characteristics such as symmetric radiation pattern, low cross polarization and stable pattern over the operating bandwidth. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 1670–1672, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21709
    Microwave and Optical Technology Letters 08/2006; 48(8):1670 - 1672. DOI:10.1002/mop.21709 · 0.62 Impact Factor
  • Ka‐Ming Mak, Hang Wong, Kwai‐Man Luk
    [Show abstract] [Hide abstract]
    ABSTRACT: A high-gain wideband low-profile microstrip patch antenna array is designed and tested. A method for enhancing the impedance bandwidth through the combination of a driven rectangular patch with parasitic elements is proposed. The array, which has 16 elements in a 4 × 4 arrangement, is pasted on a 2-mm dielectric substrate. The impedance bandwidth and the gain of the array is 12% (for SWR ≤ 2) centered at 4.5 GHz and 20 dBi, respectively. © 2006 Wiley Periodicals, Inc. Microwave Opt Technol Lett 48: 729–730, 2006; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/mop.21458
    Microwave and Optical Technology Letters 04/2006; 48(4):729 - 730. DOI:10.1002/mop.21458 · 0.62 Impact Factor
  • H. Wong, PY Lau, K.-M. Mak, K.-M. Luk
    [Show abstract] [Hide abstract]
    ABSTRACT: A small circularly polarised (CP) patch antenna with dual T-shaped probe feeds is presented. The patch is folded like a cap to generate a CP wave as well as to reduce the size of the antenna. The proposed antenna is operated at the centre frequency of 2.28 GHz with circular polarisation. The impedance bandwidth (SWR<2) is 21.8% from 2 to 2.49 GHz and the axial ratio bandwidth (AR<3 dB) is 3.5%. The measured gain is around 7.5 dBi. The antenna shows a good CP performance with a symmetric radiation pattern. The total area of reduction is 54% in comparison with the conventional half-wave patch antenna.
    Electronics Letters 01/2006; 41(25-41):1363 - 1365. DOI:10.1049/el:20053677 · 1.07 Impact Factor

Publication Stats

82 Citations
9.63 Total Impact Points

Institutions

  • 2009–2014
    • The University of Hong Kong
      • Department of Electrical and Electronic Engineering
      Hong Kong, Hong Kong
  • 2007–2012
    • City University of Hong Kong
      • • State Key Laboratory of Millimeter Waves
      • • Department of Electronic Engineering
      Chiu-lung, Kowloon City, Hong Kong