Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 10s (2025) 2748 https://internationalpubls.com Quad band Frequency Tunable Patch Antenna for Different Wireless Applications Vijayluxmi1, Prem Pal Singh2, Sudhir Kumar Sharma3, Chetan Singh Meena4 1Assistant Professor, Department of Electronics & Communication Engineering, RPIIT, Bastara, Haryana, India. 2Assistant Professor, Department of Electronics & Communication Engineering, Parul University, Vadodara, Gujarat, India. 3Head, Department of Electronics & Communication Engineering, Jaipur National University, Jaipur, India 4Scientist, Defence Research and Development Organization, New Delhi, India Corresponding authors, email address: vijayluxmimeena@gmail.com, prempal.singh38023@paruluniversity.ac.in and Sudhir.732000@gmail.com Article History: Received: 12-01-2025 Revised: 15-02-2025 Accepted: 01-03-2025 Abstract: This paper describes the design and development of a 14mmx23mm tiny quad-band reconfigurable antenna. Four different bands are covered by the antenna's efficient operation design: 4.10 GHz, 3.75 GHz, 5.60 GHz, and 4.60 GHz. Through simulation the antenna's performance characteristics—such as radiation pattern, gain, and impedance matching are thoroughly examined. Innovative tuning techniques using the BAR50-02V PIN diode enable the antenna to be reconfigured, providing reliable performance in all designated bands. This antenna can be integrated into modern wireless communication systems that require flexible frequency operation due to its compact size and multi-band flexibility. Keywords: Reconfigurable antenna, PIN diode, Cognitive radio, Tunable antenna, Multiband antenna. 1. Introduction The potential to vary features like radiation pattern and frequency spectrum makes reconfigurable antennas important for present communication organization. They make it promising to operate flexible across a range of frequency bands, which improve the use of spectrum and encourage compatibility between system types [1] Reconfigurable antennas improve performance parameters including impedance matching, gain, and efficiency by dynamically changing their configuration. This enables dependable signal transmission under a range of propagation situations. Because of their flexibility, which combines several functions into a single antenna, they support valuable use of existing space and minimize the equipment costs. Reconfigurable antennas also enhance communication confidentiality and reduce interference, which both improve security. In software- defined radio and cognitive radio applications, they play a critical role in enabling dynamic spectrum access and standardization of communication protocols. Overall, reconfigurable antennas provide features that are future-proof, flexible, and efficient [2]. The antenna is 120x120 mm in size and shows good performance with -28 dB return loss at 0.98 GHz and -14 dB at 1.84 GHz. It uses fractal designs to work effectively in two frequency bands [5]. A new dual band antenna configuration with a compact dimension of 55x50mm2, which has a 0.882dB and 2.108dB gain, respectively, at 4.2 GHz and 5.6 GHz frequency featuring T-shaped and small rectangular gaps in the ground plane [3]. The aim of this mailto:vijayluxmimeena@gmail.com mailto:prempal.singh38023@paruluniversity.ac.in mailto:Sudhir.732000@gmail.com Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 10s (2025) 2749 https://internationalpubls.com new design is enhancing each band's bandwidth and resonant frequencies for both WiMAX and IMT frequency bands. CST MW was used in the design and optimization of this quasi-omnidirectional antenna. Triband 53.37x75.20 sized modified fractal slot antenna with CPW feeding is tailored for achieving multiple resonant frequencies 1.8 GHz, 3.5 GHz and 5.2 GHz with Return loss S(1,1) dB- 17.2, -22.5 , -35 5 suitable for DCS1800, WiMAX, IMT-Advanced, and 4G mobile communication systems. Its design allows for a bidirectional radiation pattern across the specified frequency bands, making it a versatile choice for digital communication applications [4]. In [6] introduces a compact, frequency-reconfigurable printed patch antenna measuring 35x 47, utilizes a microstrip feed connected to a circular radiating element divided into three patches. These patches incorporate silicon PIN diodes as switches for achieving frequency reconfigurability. The antenna includes slots of various shapes etched into the patches to cover multiple WLAN frequency bands (2.4 GHz, 3.6 GHz, 4.9 GHz, 5.1 GHz, and 5.9 GHz).A bias tee is designed to supply DC bias to the PIN diodes, essential for their function. An experimental result from a fabricated prototype and simulated data reveals good agreement, confirming the antenna's effectiveness in achieving reconfigurability across the specific frequency bands. [7] While optical switches are simple to integrate, their placement in the antenna's plane may compromise the radiating structure's efficiency. It does not include the DC bias into the antenna or cover the lower WLAN bands. It is 50x46 in dimension and covers the frequencies 3.6 GHz, 4.9 GHz, and 5.1 GHz. Its expense and complexity are a drawback. respectively. But has a backdrop as the frequency range increases from 1.8 GHz to 5.4GHz, its radiation efficiency degraded from 73% to 59% simultaneously. A small size 22×26mm2 reconfigurable patch antenna for wireless communication applications designed and can be tuned in four different frequencies 3.6GHz,4.1GHz,6.6GHz and 8.8GHz with 1.14dBi 0.58dBi 2.46dBi, 2.95dBi gains respectively in [1]. 2. Antenna Design Methodology 2.1. Geometry of the Antenna The proposed antenna has two-layer geometry. The top layer is a patch made up of a rectangular radiator fed by a 50 Ω microstrip line of resistance and featuring a slotted construction. With dimensions of 14x23 mm³ and a dielectric constant of 4.4, the antenna was simulated and fabricated on FR-4 substrate material, which has superior insulating qualities and can increase antenna efficiency. The ground plane was also altered to control the bandwidth. Two PIN diodes in total are integrated for the purpose of reconfiguration. PIN diodes are designed using lumped elements during the design simulation. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 10s (2025) 2750 https://internationalpubls.com Figure 1. Geometry of the Antenna Dimensions of final design summarized in table Table 1: Optimized parameters of the suggested antenna Parameter Value (mm) Parameter Value (mm) L 23 W 14 L1 13.6 W1 2.8 L2 6 Wg 13 L4 0.9 Lg 5.4 L5 5.5 L10 1.5 L6 3.6 W2 10.8 L8 2.4 W3 7 L9 0.9 W4 5.3 W6 1.3 W5 9 W8 4.7 W9 4.8 Equivalent circuit of the used PIN diode and parameter values BAR50-02V is shown in figure.2 and table 2 respectively. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 10s (2025) 2751 https://internationalpubls.com Figure 2. PIN diode equivalent diagrams (a) ON state (b) OFF state Table 2: Element values of BAR50-02V PIN Diode Model State L1 CT RP RS BAR50- 02V OFF 0.15pF 3KΩ ON 0.6nH 3Ω DIODE TEST CASE ANALYSIS Case 1: Diode 1 is OFF and Diode 2 is OFF Figure 3. Return Loss v/s Frequency The graph predicts that frequency 4.10GHz is obtained whenever Diode 1 and Diode 2 are in OFF condition. Case 2: Diode 1 is OFF and Diode 2 is ON Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 10s (2025) 2752 https://internationalpubls.com Figure 4. Return Loss v/s Frequency The frequency of 4.13GHz is obtained which can be used as a WLAN channel is obtained in 01 condition. Case 3: Diode 1 is ON and Diode 2 is OFF Figure 5. Return loss v/s Frequency The frequencies are of 3.75GHz and 5.60 GHz is obtained when Diode 1 is ON and Diode 2 is OFF. Both 3.75 GHz and 5.60 GHz are important for modern wireless communication, including 5G, wi-fi, and radar systems. Their selection depends on the balance needed between range, data rate and interference resistance. Case 4: Diode 1 is ON and Diode 2 is ON Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 10s (2025) 2753 https://internationalpubls.com . Figure 6. Return loss v/s Frequency The above graph is plotted between Freq v/s. S11. Frequency 4.60 GHz obtained in this condition. 3. Results and Discussion. Table 3: Resonating Frequency and Gain for Different combinations of Diode Case Configuration of Diodes Resonating Frequency (GHz) (Simulated) S11 Gain (dBi) D1 D2 Case 1 0 0 4.10 -31.99 1.2 Case 2 0 1 4.15 -30.99 1.2 Case 3 1 0 3.75,5.60 -16.20 1.8 Case 4 1 1 4.60 -41.41 1.6 The table shows how different diode configuration affect the resonating frequency and gain of a reconfigurable antenna. In case 1 (D1=0, D2=0) and case 2 (D1=0, D2=1), the antenna resonates at around 4.10-4.15 GHz, suitable for mid-band 5G, radar, and satellite communication. Case 3 (D1=1, D2=0) gives dual frequencies of 3.75GHz and 5.60 GHz, which are useful for Wi-Fi applications. This case also shows the highest gain of 1.8 dBi, making it ideal for strong, efficient signal transmission. Case 4 (D1=1, D2= 1) resonates at 4.60GHz, supporting advanced 5G and military communication systems. It has the best S11 value, indicating excellent impedance matching and low reflection. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 10s (2025) 2754 https://internationalpubls.com 4. Radiation and Gain Pattern (a) (b) (c ) (d) Figure 7. Radiation Pattern of Proposed Antenna for Diodes configuration (a) 00 (b) 01 (c) 10 (d) 11 (a) (b) (c) (d) Figure 8. Gain plot of Antenna for Diodes configuration (a) 00 (b) 01 (c) 10 (d) 11 Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 10s (2025) 2755 https://internationalpubls.com Table 4: Comparative Analysis Paper Size (mm2) Frequencies (GHz) Reconfiguration Technique Complexity 3 55x50 4.2,5.6 PIN Simple 4 53.37x75.20 1.8,3.5,5.2 PIN Moderate 5 120x120 0.98,1.84 PIN Large 6 35 x 47 2.4,3.6, 4.9, 5.1, 5.9 PIN Moderate 7 50x46 3.6,4.9,5.1 Physical Rotation Optical Switching Complex and Costly Proposed work 14x23 3.62, 4.02, 4.59 , 5.19 PIN Simple 5. Conclusion In this work, an extremely compact (14 mm × 23 mm) quad-band reconfigurable antenna that can function effectively in four different frequency bands—4.10 GHz, 3.75 GHz, 5.60 GHz, and 4.60 GHz—is designed and developed. Through modeling, all of the antenna's performance parameters— such as radiation pattern, gain, and impedance matching are carefully assessed. Innovative tuning methods that make use of the BAR50-02V PIN diode are essential to its adaptability since they allow for a smooth reconfiguration for dependable performance in all specified bands. The antenna's seamless integration into contemporary wireless communication systems that demand flexible frequency operation is made possible by this characteristic. Applications for wireless communication, radar systems, satellite communication, medical equipment, scientific instruments, industrial automation, and Internet of Things deployments are among the many that are served by the antenna's wide range of frequency bands. Acknowledgements I would like to thank Rajasthan University to provide testing facility and Jaipur National University to conduct research on this work. References [1] Dr. B. Baranidharan, Anu Maria Joykutty, Cognitive Radio Networks: Recent Advances in Spectrum Sensing Techniques and Security Proceedings of the International Conference on Smart Electronics and Communication (ICOSEC 2020) IEEE Xplore Part Number: CFP20V90- ART; ISBN: 978-1-7281-5461-9 [2] T.Khan, M.Rahman, A. Akram, Y.Amin, and H. Tenhunen (2019) A Low-cost CPW-Fed Multiband Frequency Reconfigurable Antenna for Wireless Applications, Multidisciplinary Digital Publishing Institute, Electronics, vol. 8, 1-17, https://doi.org/10.3390/electronics8080900 [3] Zahraoui, Issam & Ahmed, Errkik & ZBITOU, JAMAL & Tajmouati, Abdelali & Mediavilla, Angel. (2016). A novel design of a fractal antenna for IMT and WiMAX applications. Communications on Applied Nonlinear Analysis ISSN: 1074-133X Vol 32 No. 10s (2025) 2756 https://internationalpubls.com INTERNATIONAL JOURNAL OF MICROWAVE AND OPTICAL TECHNOLOGY, 428 VOL.11, NO.6, NOVEMBER 2016. 11. 428-434. [4] C. Mahatthanajatuphat and P. Akkaraekthalin, “A Bidirectional multiband Antenna With Modified Fractal Slot Fed By CPW”, Progress In Electromagnetics Research, pp. 59-72, Jun. 2009. [5] D. C. Chang, B. H. Zeng and J. C. 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