Filtering Antenna[1] - Read-Only (2).pptx

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1. Compact Low-Profile Wideband Filtering Antenna Without Additional Filtering Structure Dr/ Doaa Ahmed Dr/ Ahmed Magdy 1

2. Project analysis slide 2 Alyaa Mohamed Samy Yomna Mohamed Kamal Yasmin Tarek Mostafa Belal Eid Atia Mahmoud Mohamed Doaia Omar Elsayed Salama Project Members 2

3. Project analysis slide 2 Project Analysis PROJECT Topics Introduction Simulation Theory Result Conclusion 3

4. By : Alyaa Mohamed Samy Introduction 4

5. Project analysis slide 3 Project introduction Advantages ECOLOGICALIS Flexible design Easy to adjust/filt er Benefits: Generates two radiation nulls Adds a new resonance ➝ wider bandwidth Simple structure with high filtering performance Drawbacks: Increased size Insertion loss . Complex matching Higher cost No additional filtering structures Low-profile and wideband Based on: A semicircular slot Inverted Y-shaped branches Quarter-wavelength matching line In traditional wireless communication systems, antennas and filters are designed as separate components, each serving its own purpose: the antenna radiates signals, while the filter suppresses unwanted frequencies. This modular approach offers design flexibility and ease of tuning Traditional RF Front-End Challenges In conventional wireless systems:   A Compact Wideband Filtering Antenna   : Antenna handles radiation. Filter suppresses unwanted frequencies. They are designed separately and connected via matching circuits Peak gain (~4.92 dBi ) is lower than multi-layer or high-profile designs. 2. High Sensitivity to Dimensions Small fabrication errors can shift resonance or reduce filtering accuracy. Drawbacks: 5

6. BY: YOMNA MOHAMED KAMAL Theory 6

7. THEORY -Compact, Low-Profile Wideband Filtering Antenna : Achieves filtering performance without  needing extra filtering components. -Elements That Enable Filtering: 1-Semicircular-Shaped Wide Ground Slot Acts as a primary resonator. Creates the main resonance frequency (~6 GHz). On its own, it provides narrow impedance bandwidth (~13.1%). Does not generate radiation nulls, so no filtering effect alone. 2-Inverted Y-Shaped Symmetrical Branches Placed symmetrically within the semicircular slot; they modify current distribution. Introduce a new resonant frequency in the lower band → broader impedance bandwidth (expanded to 31.6%). Create two radiation nulls at: 3.36 GHz (lower stopband) 7.74 GHz (upper stopband) Nulls are due to opposite current flows (cancellation) → effectively filter out unwanted signals outside the desired band.  This structure is responsible for band broadening + filtering without additional components. 7

8. 3-Quarter-Wavelength Impedance Matching Line Added to the feedline (front end). Improves impedance matching → lower reflection (S11 < −10 dB). Enhances gain flatness and radiation efficiency within the passband. Does not directly create filtering, but optimizes performance in the working band. 4-Surface Current Distribution (Current Cancellation) At 3.4 GHz and 7.68 GHz, currents flow in opposite directions in the Y-branches and ground plane. This cancels radiation → produces radiation nulls. This is the physical reason behind filtering performance. Ensures signal suppression at undesired frequencies. 5- Tunable Geometry (Dimensions l2 and w1) l 2 (length of Y-branch): Controls upper radiation null frequency. w1 (width of Y-branch): Affects both upper and lower nulls, shifts passband. Allows custom tuning of filtering frequencies without redesigning the whole antenna. 8

9. By : Yasmin Tarek Mostafa Simulation 9

10. Steps of Simulation Implementation ___________________________________ The antenna was designed and simulated using CST Studio Suite 2024 Substrate Layer 🔹 Material: FR-4 lossy 🔹 Dimensions: Length: 35 mm Width: 29 mm Thickness: 0.8 mm Role: Supports the antenna structure and affects wave propagation. 10

11. Steps of Simulation Implementation _________________________________ 2. Ground Plane Material: PEC (Perfect Electric Conductor) Shape : Full rectangular ground with a semicircular slot.   Dimensions: Length: 35 mm Width: 29 mm Thickness: 0.035 mm Slot: Shape: Semicircular Radius: ~14 mm Created using subtract operation 11

12. Steps of Simulation Implementation _________________________________ 3. Inverted Y-Shaped Material: PEC (Perfect Electric Conductor) Dimensions: Length (l2) = 6 mm Width (w1) = 14.5 mm Placement: Symmetrical, connected to the ground around the slot. Tuning Note: l2 controls upper radiation null. w1 affects overall bandwidth. 12

13. Steps of Simulation Implementation _________________________________ 4. Microstrip Feed Line Material: PEC (Perfect Electric Conductor) Dimensions: Feedline width ( w4 ): 1.6 mm Feedline length ( l4 ): 15 mm Matching section: Width ( w5 ): 2.1 mm Length ( l5 ): 10 mm Placement: Top side of the substrate. Feeds RF energy into the antenna 13

14. Steps of Simulation Implementation _________________________________ 5. Waveguide Port Placement: Positioned at the start of the microstrip feedline Oriented to excite the antenna from the edge Frequency Range: Start: 3 GHz Stop: 10 GHz Covers: Operating band (4.67–6.53 GHz) "After setting the design parameters, we proceeded to start the simulation..." 14

15. What Was Simulated in the Project? 1. S-Parameter (Signal Reflection – |S11|) Result from Simulation: |S11| was below −10 dB in the frequency range from 4.67 GHz to 6.42 GHz, which defines the effective operating bandwidth of the antenna. 2. Gain & Radiation Nulls (Performance at Band Edges) Result: The surface currents on the Y-shaped branches flow in opposite directions, effectively canceling each other out → resulting in no radiation (natural filtering effect). 3. Parametric Study What Was Changed: l2: Increasing this length shifted the upper null frequency down. w1: Affected both null frequencies (the entire band shifted). Specific dimensions can be adjusted to control the filtering behavior of the antenna. 4. surface Current Distribution Result: The surface currents on the Y-shaped branches flow in opposite directions, effectively canceling each other out → resulting in no radiation (natural filtering effect). 5. Radiation Patterns Result: The antenna showed a stable and nearly symmetric radiation pattern, making it suitable for communication applications. 15

16. By : Mahmoud Mohamed Doaia Result 16

17. Results S11 :represents how much power is reflected from the antenna and is known as reflection cofficient . Simulation and measurement results of the S-parameter, peak realized gains in the direction of theta = 160° and phi = 0°, and radiation efficiency considering the impedance-mismatching loss of the proposed filtering antenna. The simulated and measured S-parameters are in good agreement, and the simulated and measured 10 dB impedance bandwidths are about 31. 6% (4. 67–7.11 GHz) and 33. 2% (4. 67–6. 53 GHz), respectively 17

18. Realized Gain :in this gain we takes into account reflection losses. The measured gain curve of the antenna in the passband is flat with an average realized gain of 4.64 dB and peak realized gain of 4.92 dB.    Two radiation nulls are generated at 3.36 and 7.74 GHz, indicating the high selectivity of the proposed antenna.   The simulated radiation efficiency is greater than 80% over the entire operating frequency band, and the trend of the radiation efficiency curve is consistent with the realized gain curve.  It reveals that due to impedance mismatch, radiation from all directions of the proposed filtering antenna is suppressed, not just in the peak gain direction. 18

19. 19 Definition of Farfield In antenna theory, the farfield region (or Fraunhofer region) is the area far away from the antenna, where: The electromagnetic waves radiated by the antenna behave like plane waves. The angular field distribution becomes independent of the distance from the antenna. It is the region used for measuring radiation patterns, gain, and directivity accurately. Rule of thumb : The farfield starts at a distance R>2D*2/λ D = largest dimension of the antenna λ = wavelength Radiation Pattern at Phi = 90° : Red curve: Represents the radiated power (directivity) at different angles (Theta). Theta axis: Angular direction in degrees (0° to 180°). dBi : Decibels over isotropic radiator (a measure of directivity).

20. 20 Data from the plot: Frequency : 5 GHz — the antenna operates at this frequency. Main lobe magnitude: 5.71 dBi — strongest radiation direction. Main lobe direction: 149.0° — the direction of peak radiation. Angular width (3 dB): 59.6° — beamwidth of the main lobe, where power drops by 3 dB. Side lobe level: -0.9 dB — secondary peaks in radiation; this is low, indicating good directivity. In Simple Terms The graph shows how well the antenna sends energy in different directions at 5 GHz. Most of the energy is sent at 149°, and the signal is very directional (focused). The side lobes are weak, meaning less unwanted radiation in other directions.

21. By : Omar Elsayed Salama Conclusion 21

22. Filtering Wide-Slot Antenna Design A symmetrical inverted Y-shaped branch was added to a traditional semicircular wide-slot antenna structure. This addition introduced a new resonance frequency, which led to a broader impedance bandwidth and improved frequency performance. The design naturally generated two radiation nulls on either side of the passband, significantly enhancing the frequency selectivity. These filtering capabilities are achieved without external filtering components, resulting in a simpler and more integrated antenna structure. The final antenna is compact in size, measuring only 0.65λ₀ × 0.54λ₀ × 0.01λ₀, making it suitable for modern wireless systems with space constraints. 22

23. Performance highlights _________________________________ Impedance bandwidth of 33.2% (4.67–6.53 GHz) Peak realized gain of 4.92 dBi Stable far-field radiation patterns Flat gain response within the passband Excellent out-of-band suppression The proposed antenna combines compactness, high performance, and effective built-in filtering, making it a promising solution for next-generation wireless communication systems 23

24. References: [1] F. Queudet, I. Pele, B. Froppier, Y. Mahe, and S. Toutain, “Integration of pass-band filters in patch antennas,” in Proc. 32nd Eur. Microw. Conf., 2002, pp. 685–688. [2] J. Zuo, X. Chen, G. Han, L. Li, and W. Zhang, “An integrated approach to rf antenna-filter co-design,” IEEE Antennas Wireless Propag. Lett.,vol.8, pp. 141–144, 2009.   [3] C.-T. Chuang and S.-J. Chung, “Synthesis and design of a new printed f iltering antenna,” IEEE Trans. Antennas Propag., vol. 59, no. 3, pp. 1036–1042, Mar. 2011.   [4] C.-K. Lin and S.-J. Chung, “A compact filtering microstrip antenna with quasi-elliptic broadside antenna gain response,” IEEE Antennas Wireless Propag. Lett., vol. 10, pp. 381–384, 2011.   [5] Y.-J. Lee, J.-H. Tarng, and S.-J. Chung, “A filtering diplexing antenna for dual-band operation with similar radiation patterns and low cross polarization levels,” IEEE Antennas Wireless Propag. Lett., vol. 16, pp. 58–61, 2017. 24

25. Thank you 25