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Characteristics of the Angled Printed Dipole Array Antenna with Different Numbers of Dipole Elements
Heesu Wang,Ikmo Park 한국전자파학회JEES 2020 Journal of Electromagnetic Engineering and Science Vol.20 No.3
This paper investigated the characteristics of series-fed angled dipole antennas as the number of dipoles increased from one to two, four, and eight. A parallel strip line printed on both sides of the substrate was used to connect angled printed dipoles of the same size in a series with equal spacing. As expected, although the gain increased as the number of dipoles increased, the impedance and gain bandwidths decreased. In addition, as the number of dipoles increased, the half-power beamwidth (HPBW) differences between the xz- and yzplanes decreased and the radiation pattern of the xz-plane became more symmetric. Antennas with one, two, four, and eight-dipole elements in a series were designed, and their peak gains were 5.0 dBi, 7.2 dBi, 9.4 dBi, and 10.4 dBi, respectively. The differences between the xz- and yz-plane HPBWs of the four antennas were 160.4°, 41.7°, 14.2°, and 5.3°, respectively. As the number of dipoles in the antenna increased, the differences between the HPBWs in the xz- and yz-planes decreased.
Compact Slot Antenna Integrated with a Photovoltaic Cell
Ahmed Ali,Heesu Wang,Yeojun Yun,Jaejin Lee,Ikmo Park 한국전자파학회JEES 2020 Journal of Electromagnetic Engineering and Science Vol.20 No.4
This paper presents a compact low-profile slot antenna integrated with a photovoltaic cell. The photovoltaic cell consists of a top metal grid, gallium arsenide substrate, and metallic bottom contact. The metallic bottom contact was used as a ground plane where the slot was etched for resonance. A second substrate was placed under the ground plane, and a 50 Ω microstrip line was printed on its bottom side to excite the slot. A chip inductor was used as a radio frequency (RF) choke in the alternating current blocking circuit to suppress RF current leakage towards the photovoltaic cell. Hence, the proposed antenna has a unique feature of functioning simultaneously as a photovoltaic cell and an antenna. The overall dimensions--25 mm × 31.75 mm × 0.893 mm (0.48o × 0.61o × 0.017o at 5.77 GHz)--of the photovoltaic cell-integrated slot antenna structure can be used effectively with Internet of Things devices.
Kam Eucharist Kedze,Heesu Wang,Ikmo Park 한국전자파학회JEES 2019 Journal of Electromagnetic Engineering and Science Vol.19 No.2
This paper presents the effects of the position of the split of a split-ring resonator (SRR) on the performance of a composite broadband printed dipole antenna. The antenna is made of two printed dipole arms enclosed by two rectangular and identically printed SRRs. One dipole arm and the SRR are printed on the top side of the substrate, while the other dipole arm and SRR are printed on the bottom side of the same substrate. By changing the position of the split on the SRR, different antenna characteristic values are obtained, namely, for impedance bandwidth and radiation patterns. The split position is thus a critical parameter in antenna design, because it influences the antenna’s major performance immensely. Different split positions and their consequences for antenna performance are demonstrated and discussed. The antenna generates linearly polarized radiations, and it is computationally characterized for broadband characteristics. The optimized compact antenna has overall dimensions of 9.6 ㎜ × 74.4 ㎜ × 0.508 ㎜ (0.06λ × 0.469λ × 0.0032λ at 1.895 ㎓) with a measured fractional bandwidth of 60.31% (1.32 to 2.46 ㎓ for |S11| < –10 ㏈) and a radiation efficiency of >88%.
Coplanar Waveguide-Fed Bidirectional Same-Sense Circularly Polarized Metasurface-Based Antenna
Cho Hilary Scott Nkimbeng,Heesu Wang,Ikmo Park 한국전자파학회JEES 2021 Journal of Electromagnetic Engineering and Science Vol.21 No.3
This paper presents the design of a bidirectional same-sense circularly polarized (CP) antenna that uses metasurfaces. The antenna consists of two metasurfaces, each comprising an array of 2 × 4 corner truncated patches placed back-to-back on the top and bottom of the antenna. In addition, a ground plane with an etched slot is sandwiched between the substrates at the front and back, and the feed line is a 50 Ω coplanar waveguide. The antenna radiates same-sense right-handed CP waves in both the front and back directions and has overall dimensions of 48 ㎜ × 24 ㎜ × 3.048 ㎜ (0.91λ。 × 0.45λ。 × 0.05λ。 at 5.7 ㎓). The measured reflection coefficient for |S11| < -10 ㏈ yields an impedance bandwidth of 5.21–6.26 ㎓ (18.4%) and an axial ratio (AR) bandwidth of 5.36–6 ㎓ (11.2%) for both front and back directions. The antenna gain is 3–5.29 ㏈ic for both directions and has a radiation efficiency of >96% within its AR bandwidth.