WEEKLY SEMINAR Sunryul Kim 2019.01.30

12th European Conference on Antennas and Propagation (EuCAP 2018) Paper Review I Paper Review II A Compact Low Cost High Isolation Substrate Integrated Waveguide Fed Slot Antenna Array at 28 GHz employing Beamforming and Beam Scanning for 5G Applications 12th European Conference on Antennas and Propagation (EuCAP 2018) SUMMARY GEOMETRY FREQUENCY 28 GHz STUCTURE SIW fed slot Antenna FEATURE Compact Low cost (FR308HR substrate) High isolation (below -25 dB) Wideband (3.685GHz, 13.1%) Fig.1 Antenna geometry

SINGLE ANTENNA ELEMENT Paper Review I Paper Review II SINGLE ANTENNA ELEMENT ANTENNA ARRAY DESIGN CONSIDERATIONS There are two design rules related to the pitch, via diameter and cut-off frequency. (1) (3) (2) The equivalent SIW width “Ae” is the width of rectangular waveguide whose modes exhibit the same propagation characteristics of the SIW modes. Fig.2 SIW Slot Antenna “P” and “D” control the radiation loss and return loss. “Ar” determine the cut-off frequency and propagation constant of the fundamental mode. (4) (5) “a” is the broadside dimension of the air filled rectangular waveguide.

SINGLE ANTENNA ELEMENT Paper Review I Paper Review II SINGLE ANTENNA ELEMENT ANTENNA ARRAY CONSIDERATIONS FINAL DESIGN The dimensions of the slot are in multiples of λ/4 and optimized for maximum matching. The position of the slot is kept at electrical maxima (3λ/4) in the SIW for maximum coupling. Fig.2 SIW Slot Antenna Fig.2 Realized prototype of proposed antenna

SINGLE ANTENNA ELEMENT Paper Review I Paper Review II SINGLE ANTENNA ELEMENT ANTENNA ARRAY S-PARAMETER RADIATION PATTERN 4.7 dBi ? 26 GHz 29.56 GHz Fig.3 Simulated and Measured S11 (dB) vs Frequency Fig.4 Radiation pattern showing gain of the antenna The proposed antenna is matched in a frequency range of 26 GHz to 29.56 GHz. The single element gain is 4.7 dBi.

SINGLE ANTENNA ELEMENT Paper Review I Paper Review II SINGLE ANTENNA ELEMENT ANTENNA ARRAY ARRAY DESIGN RADIATION PATTERN Fig.5 5 SIW fed Slot Antenna Array elements placed at 0.5 λ excited simultaneously Fig.6 Combined Radiation Pattern (Beam forming) at 0.5 λ inter element spacing An SIW fed slot antenna array of 5 elements is placed at 0.5λ inter-element spacing is shown in figure 5. Maximum gain is 10 dBi and the half power beam width is 30˚.

SINGLE ANTENNA ELEMENT Paper Review I Paper Review II SINGLE ANTENNA ELEMENT ANTENNA ARRAY ISOLATION COMPARISON Fig.8 Isolation in a 5-element patch array for 0.5λ inter-element spacing Fig.7 High isolation between radiating elements at 0.5λ inter-element spacing. The isolation in patch array is -16 dB for same inter-element spacing. Without employing any decoupling techniques one can achieve sufficient isolation in an array using SIW. The isolation between the array elements at 0.5λ inter-element spacing is below -25 dB both in simulations and measurements.

SINGLE ANTENNA ELEMENT Paper Review I Paper Review II SINGLE ANTENNA ELEMENT ANTENNA ARRAY SCANNING SCANNING PATTERN In the case of patch antenna, the higher the beem steering angle, the lower the gain. It also produces an error while scanning to a specific angle, that is, if scan angle is 60˚ it might only scan to 45˚ or 50˚ depending upon the isolation. Fig.9 60˚ Beam Scanning It can be observed that the main beam is exactly scanned to the required scan angle. This is because of the high isolation of the antenna array.

Paper Review I Paper Review II 28/38-GHz Dual-Band Millimeter Wave SIW Array Antenna with EBG Structures for 5G Applications 2015 International Conference on Information and Communication Technology Research (ICTRC2015) SUMMARY GEOMETRY FREQUENCY 28/38 GHz STUCTURE Slotted-SIW Antenna SINGLE ANTENNA BANDWIDTH 0.45 GHz (1.6 %) at 28 GHz 2.20 GHz (5.8 %) at 38 GHz SINGLE ANTENNA GAIN 5.2 dBi at 28 GHz 5.9 dBi at 38 GHz ARRAY BANDWIDTH 0.32 GHz (1.14 %) at 28 GHz 1.9 GHz (5 %) at 38 GHz ARRAY GAIN 11.9 dBi at 28 GHz 11.2 dBi at 38 GHz Fig.10 Antenna geometry

SINGLE ANTENNA ELEMENT Paper Review I Paper Review II SINGLE ANTENNA ELEMENT ANTENNA ARRAY DESIGN S-PARAMETER Fig.11 Slotted-SIW single antenna element front view RT/duroid 5880 (εr = 2.2 , tanδ = 0.003) Thickness : 0.254 mm Diameter of via holes : 0.50 mm Via-to-via distance : 1 mm Fig.12 Dual-band SIW single antenna element reflection coefficient (S11). The impedance bandwidth (S11 < -10dB) is 0.45 GHz (27.72 – 28.17 GHz) and 2.20 GHz (36.70 – 38.90 GHz) around 28 GHz and 38 GHz respectively.

SINGLE ANTENNA ELEMENT Paper Review I Paper Review II SINGLE ANTENNA ELEMENT ANTENNA ARRAY RADIATION PATTERN Fig.13 E-plane radiation pattern at 28 GHz, 38 GHz (single element) Fig.14 H-plane radiation pattern at 28 GHz, 38 GHz (single element) The cross-pol levels are less than -25 dB in both planes. The antenna exhibits good radiation characteristics in terms of back radiation and side lobe levels. The maximum value of gain is found to be 5.2 dBi and 5.9 dBi at 28 GHz and 38 GHz, respectively.

SINGLE ANTENNA ELEMENT Paper Review I Paper Review II SINGLE ANTENNA ELEMENT ANTENNA ARRAY ARRAY S-PARAMETER Fig.15 Dual-band 1 × 4 slotted SIW antenna array. Distance between the adjacent radiating elements is around λg (guided wavelength at 28 GHz). The array is fed by 1 × 4 Wilkinson power divider surrounded by electromagnetic bandgap (EBG) structures. To improve the array radiation characteristics, a ground structure based on a compact uniplanar EBG unit cell has been used. Fig.16 Dual-band 1 × 4 slotted SIW antenna array reflection coefficient (S11). The impedance bandwidth (S11 < -10 dB) of 0.32 GHz (27.95 GHz – 28.27 GHz) and 1.90 GHz (37.29 GHz – 39.19 GHz) is achieved around 28 GHz and 38 GHz respectively.

SINGLE ANTENNA ELEMENT Paper Review I Paper Review II SINGLE ANTENNA ELEMENT ANTENNA ARRAY E-FIELD DISTRIBUTION (a) (b) Fig.17 Simulated electric field distribution at (a) 28 GHz. (b) 38 GHz. At 28 GHz, the array of slot 1 is radiating at its maximum level. Similarly, the wave propagation inside the SIW cavity structure at 38 GHz is not disturbed by the array of slot 1 and eventually it is radiated through the array of slot 2.

SINGLE ANTENNA ELEMENT Paper Review I Paper Review II SINGLE ANTENNA ELEMENT ANTENNA ARRAY RADIATION PATTERN Fig.18 E-Plane radiation pattern at 28 GHz, 38 GHz (1×4 Array) Fig.19 H-Plane radiation pattern at 28 GHz, 38 GHz (1×4 Array) The gain values at the respective frequency bands are 11.9 dBi and 11.2 dBi, respectively.

IDEA 28GHz 5G 단말용 배열안테나 목표 Magneto-electric dipole Self-Complementary 인체 둔감성 격리도 향상 빔 조향 성능 향상 빔 폭 확장 Magneto-electric dipole 광대역 특성 인체에 의한 공진주파수 이동에 내성을 가짐 후방방사 상쇄 인체영향을 줄일 수 있을 것으로 예상 Substrate Integrated Waveguide 높은 격리도 빔 조향 성능 향상 Fractal Self-Complementary 광대역 특성 인체에 의한 공진주파수 이동에 내성을 가짐 Magnetic half Wire 안테나에 비해 efficiency, gain, human-body power loss 특성이 좋음 Slot Magnetic Efficiency, gain, human-body power loss 특성이 좋음 Circular polarization 목표에 부합하는 장점은 찾지 못하였음

IDEA SIW fed slot antenna SIW fed magneto-electric dipole Upper side : Magnetic dipole Lower side : Magnetic loop

THANK YOU