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Design and Analysis of Planar Frequency Doubling Reflectenna for IoT 

Sensor Networks 

 

Anil M Kasture1, Kailash J Karande2, Shankar D Nawale3, Altaaf O Mulani4 

1Research scholar, SKN Sinhgad College of Engineering, Korti, Pandharpur, Dist Solapur, 

Maharashtra, India. 

2 Principle & Professor, SKN Sinhgad College of Engineering, Korti, Pandharpur, Dist Solapur, 

Maharashtra, India. 

3 Principle & Professor, N B Navale Sinhgad College of Engineering, Kegaon, Solapur, Dist Solapur, 

Maharashtra, India. 

4 HOD & Professor, SKN Sinhgad College of Engineering, Korti, Pandharpur, Dist Solapur, 

Maharashtra, India. 

Email: anilkasture01@gmail.com1, kailashkarande@yahoo.co.in2, shankarnawale125@gmail.com3, 

altaaf.mulani@sknscoe.ac.in4 

 

Article History: 

Received: 12-01-2025 

Revised: 15-02-2025 

Accepted: 01-03-2025 

Abstract:  

Compact and energy-efficient communication technologies are critical for the development of 

smart sensor networks in the constantly expanding Internet of Things (IoT) environment. This 

paper describes the design, analysis, and implementation of a compact planar frequency 

doubling reflectenna, specifically usefull for IoT sensor networks. The proposed reflectenna 

utilizes the frequency doubling phenomenon to enhance signal reception and transmission in 

IoT applications. By leveraging advanced antenna and metamaterial design principles, the 

reflectenna achieves efficient power conversion, reduced energy consumption, and enhanced 

wireless communication range. The performance of the reflectenna is analyzed through 

simulation and practical implementation, showcasing its potential as a fundamental component 

in the next generation of IoT networks. The gain of F1 antenna is 3.5 dBi and gain of mF1 

antenna is 5.1dBi. Output power for frequency doubling reflectenna system observed -20dB, -

89dB for distance between Tx and Rx at 100 cm, 1000cm respectively. 

Keywords: Frequency Doubling, Reflectenna, Compact Planar Antenna, IoT Sensor Networks, 

Metamaterials, Wireless Communication, Energy Efficiency etc. 

1. Introduction 

The introduction of the Internet of Things (IoT) has revolutionized various fields, including smart 

cities, healthcare, industrial automation, and environmental monitoring [3],[4],[5]. A critical challenge 

in IoT networks is the need for energy-efficient, compact, and reliable communication systems. IoT 

devices, particularly sensor nodes, require efficient data transmission to minimize power consumption 

while maximizing range and reliability [1],[2],[6].  

mailto:anilkasture01@gmail.com1
mailto:kailashkarande@yahoo.co.in2
mailto:shankarnawale125@gmail.com3
mailto:altaaf.mulani@sknscoe.ac.in4


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Figure 1: a) Frequency multiplier reflectenna with Interrogator for Wireless application, b) 

shows Block diagram of Microstrip antenna with inset-feed line 

A promising approach to achieve these objectives is the development of advanced antennas, such as 

reflectennas, which combine the functionalities of both reflectors and antennas. The concept of 

frequency doubling within reflectennas can further improve the overall system performance by 

enhancing the efficiency of signal reception and transmission without increasing the physical size of 

the system. Figure 1 (a) shows Frequency multiplier reflectenna with Interrogator for Wireless 

application [9],[10],[11],[12]. This paper aims to design and analyse a compact planar frequency 

doubling reflectenna that meets the specific requirements of IoT sensor networks, including size 

constraints, low power consumption, and effective signal propagation [7],[8],[13]. 

2. Proposed System 

IoT sensor networks consist of many wireless devices (nodes) that communicate with each other to 

collect and exchange data. These networks are typically characterized by the following constraints: 1) 

Limited power supply: Many IoT devices are battery-operated and must operate for extended periods 

without recharging or replacing batteries. 2) Limited communication range: To ensure connectivity, 

efficiency and long-range communication is crucial. 3) Compact size: IoT devices often have small 

form factors, limiting the space available for antennas. To address these constraints, the design of 

compact and energy-efficient antennas is key [14],[15],[16]. Frequency doubling refers to the 

phenomenon where the output signal frequency is twice that of the fundamental frequency signal. This 

can be utilized in antenna systems to improve performance, particularly in non-linear environments 

[18],[19],[20]. Equation 1 represents resonant frequency. Equation 2 represents lower cutoff 

frequency. Equation 3 represents a higher frequency of cutoff. Equation 4 represents 𝛼 value for 

parallel LC. 

𝜔0
2 =

1

𝐿𝐶
                                                   (1)  

𝜔𝑐1 = −𝛼 + √𝑎2 + 𝜔0
2                                    (2) 

𝜔𝑐2 = 𝛼 + √𝑎2 + 𝜔0
2                                       (3) 

 𝛼 = 1

2𝑅𝐶
                                               (4) 

 

Reflectennas, which combine the properties of reflectors and antennas, offer a novel solution for 

compact antenna designs. By using frequency doubling, a reflectenna can operate at higher frequencies 



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while keeping its physical size small, making it an attractive solution for IoT sensor networks. Use 

equation 5 to determine the antenna width 'W'. Utilizing equation 6, to get the effective dielectric 

constant. In this case, 'εr' represents the material's relative dielectric constant. W is the patch's width 

determined by equation 5, and 'h' is the substrate's height. Utilizing the formula found in equation 7, 

to determine ΔL. Equation 8 is the speed of light in open space, to get the patch's length. Utiliz ing 

equation 9, determine the patch's input impedance. where G1 and G2 represent the conductance of the 

patch antenna's slots #1 and #2. The odd resonant voltage distribution between the slots and underneath 

the patch is denoted by a + sign, while the even resonant voltage distribution is denoted by a - sign 

[21],[22]. Equation10 is used calculate y0 by assuming Rin(y=y0) as 50Ω and Rin(y=0). L is the length 

of the patch. The calculated value of y0 will be between 0 and L/2. We can calculate the width of 50Ω 

feedline using formula for the microstrip line. If W/h ≤ 1 we use equations 11.1 and 11.2. If W/h ≥ 1 

we use equations 12.1 and 12.2.  Figure 1 (b) shows Block diagram of Microstrip antenna with inset-

feed line [23],[24],[25]. 

𝑊 = 𝑣0
2𝑓𝑟

 √
2

ɛ𝑟+1
                                                                     (5) 

ɛ𝑟𝑒𝑓𝑓 = ɛ𝑟+1

2
+

ɛ𝑟−1

2
[1 + 12

ℎ

𝑊
]

−1/2

                                    (6) 

𝛥𝐿

ℎ
= 0.412 

(ɛ𝑟𝑒𝑓𝑓+0.3) (
𝑊
ℎ

+0.264)

(ɛ𝑟𝑒𝑓𝑓−0.258)  (
𝑊
ℎ

+0.8)
              (7) 

𝐿 = 𝑣0

2𝑓𝑟√ɛ𝑟𝑒𝑓𝑓

− 2𝛥𝐿               (8) 

𝑅𝑖𝑛 = 1

2(𝐺1±𝐺12)
                            (9) 

𝑅𝑖𝑛(𝑦 = 𝑦0) = 𝑅𝑖𝑛(𝑦=0) 𝑐𝑜𝑠2(
𝜋

𝐿
𝑦0)        (10) 

ɛ𝑟𝑒𝑓𝑓 = ɛ𝑟+1

2
+

ɛ𝑟−1

2
[(1 + 12

ℎ

𝑊
)

−0.5

+ 0.04 (1 −
𝑊

ℎ
)

2

]
 

   (11.1) 

𝑍𝑐 = ɳ 

2𝜋√ɛ𝑟𝑒𝑓𝑓

 ln (
8ℎ

𝑊
+ 0.25

𝑊

ℎ
)

 

    (11.2) 

ɛ𝑟𝑒𝑓𝑓 = ɛ𝑟+1

2
+

ɛ𝑟−1

2
(1 + 12

ℎ

𝑊
)

−0.5 

    (12.1) 

𝑍𝑐 = ɳ 

√ɛ𝑟𝑒𝑓𝑓

 [
𝑊

ℎ
+ 1.393 + 0.677 𝑙𝑛 (

𝑊

ℎ
+ 1.444)

 
]

−1

  (12.2) 

3. Implementation Techniques 

Frequency Doubling Reflectenna design consists of F1 antenna, Frequency multiplying refelectenna 

(FMC) and mF1 reflectenan with frequency doubling capabilities. Different structure for 433MHz 

frequency designed and simulated. Figure 2 (a) shows 3-D gain (dBi) radiation pattern and current 

distribution distribution of Meander Line Monopole Antenna of 433MHz. Figure 2 (b) represents 3-D 

gain (dBi) radiation pattern and current distribution distribution of Meander Line Antenna of 433MHz. 

Figure 2 (c) shows 3-D gain (dBi) radiation pattern and current distribution distribution of Microstrip 



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Antenna with Cohen-Minkowski Fractal of 433MHz. Figure 2 (d) represents 3-D gain (dBi) radiation 

pattern and current distribution distribution of Microstrip Antenna with Triangle Fractal of 433MHz. 

Figure 3 shows simulation of Microstrip antenna, radiation pattern and gain of F1 Microstrip antenna 

for 433 MHz. After comparison of different Structure of 433 MHz antennas gain, we observed that 

gain of Microstrip Patch Antenna is more.  

Figure 2: 3-D gain (dBi), radiation pattern and current distribution distribution of a) Meander 

Line Monopole Antenna, b) Meander Line Antenna, c) Microstrip Antenna with Cohen-

Minkowski Fractal, d) Microstrip Antenna with Triangle Fractal of 433MHz 

 

Figure 3: Simulation of a) F1 Microstrip antenna, b) radiation pattern and gain of F1 

Microstrip antenna for 433 MHz 

The table I represents gain of different structures of Microstrip Patch Antenna of 433MHz. The planner 

microstrip antenna is designed to operate at a fundamental frequency and exhibit a second-order 

nonlinearity, which is the key to achieving frequency doubling. F1 microstrip patch antenna serves as 

the primary radiating element, designed to operate at a fundamental frequency of F1. Different 

structure for 866 MHz frequency designed and simulated. Figure 4 (a) shows 3-D gain (dBi) radiation 

pattern and current distribution distribution of Meander Line Monopole Antenna of 866 MHz. Figure 

4 (b) represents 3-D gain (dBi) radiation pattern and current distribution distribution of Meander Line 

Antenna of 866 MHz. Figure 4 (c) shows 3-D gain (dBi) radiation pattern and current distribution 

distribution of Microstrip Antenna with Cohen-Minkowski Fractal of 866 MHz. Figure 4 (d) represents 



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3-D gain (dBi) radiation pattern and current distribution distribution of Microstrip Antenna with 

Triangle Fractal of 866 MHz.  

 

Figure 4: 3-D gain (dBi), radiation pattern and current distribution distribution of a) Meander 

Line Monopole Antenna, b) Meander Line Antenna, c) Microstrip Antenna with Cohen-

Minkowski Fractal, d) Microstrip Antenna with Triangle Fractal of 866 MHz 

Table I: Represents gain of different structures of Microstrip Patch Antenna of 433MHz 

Antenna Structure Gain (dBi) 

Meander Line Monopole Antenna 2.52 

Meander Line Antenna 2.11 

Microstrip Antenna with Cohen-Minkowski Fractal 1.94 

Microstrip Antenna with Triangle Fractal 1.93 

Microstrip Patch Antenna 3.50 

 

 

Figure 5: Simulation of a) Microstrip antenna for 866 MHz, b) Radiation pattern and gain of 

mF1 Microstrip antenna for 866 MHz by simulation 

Figure 5 shows simulation of Microstrip antenna, radiation pattern and gain of F1 Microstrip antenna 

for 866 MHz. After comparison of different Structure of 866 MHz antennas gain, we observed that 

gain of Microstrip Patch Antenna is more. The following table II represents the gain of different 



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structures of Microstrip Patch Antenna of 866 MHz. mF1 Reflectenna is used to enhance the radiation 

pattern and redirect the radiated signal, improving the efficiency of signal transmission. 

Table II: Represents gain of different structures of Microstrip Patch Antenna of 866MHz 

Antenna Structure Gain (dBi) 

Meander Line Monopole Antenna 1.99 

Meander Line Antenna 1.53 

Microstrip Antenna with Cohen-Minkowski Fractal 2.01 

Microstrip Antenna with Triangle Fractal 1.93 

Microstrip Patch Antenna 5.10 

 

The design parameters, including patch dimensions, metamaterial properties, and reflecting surface 

characteristics, are optimized for maximum performance in IoT sensor networks. The performance of 

the frequency doubling reflectenna is evaluated using electromagnetic simulation software, such as 

ADS, CADFEKO. The following metrics are considered: Frequency Doubling Efficiency, Bandwidth, 

Radiation Pattern, Return Loss, Size and Compactness etc. 

 

Figure 6: a) Simulation circuit diagram of frequency doubling system using Schottky diode, b) 

Hardware implementation of frequency doubler using Schottky diode 

 

Figure 7:  Hardware implementation of a) F1 Microstrip antenna for 433 MHz, b) mF1 

Microstrip antenna for 866 MHz 



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FMC Converting the fundamental frequency to the doubled frequency. Figure 6(a) shows simulation 

circuit diagram of frequency doubling system using Schottky diode. Figure 6(a) are implemented in 

NI Multisim. Figure 6(b) Shows Hardware implementation of frequency doubler using Schottky diode. 

Figure 7 (a) represents Hardware implementation of F1 Microstrip antenna for 433 MHz. Figure 7 (b) 

represents Hardware implementation of mF1 Microstrip antenna for 866 MHz.  

4. Result and Analysis 

Simulation results show that the proposed frequency doubling reflectenna exhibits key characteristics. 

Frequency Doubling reflectenna effectively doubles the input frequency. The antenna maintains a 

directional radiation pattern with a gain of 5.1 dB for the doubled frequency. The antenna provides a 

broad bandwidth for both the fundamental and doubled frequencies, ensuring reliable communication. 

A return loss of below -10 dB is achieved at both frequencies, indicating efficient signal transmission. 

The antenna dimensions are suitable for integration into IoT sensor nodes. Figure 11(a) shows 

hardware fabrication and implementation of frequency multiplying Reflectenna. Figure 8(a) represents 

simulated reflection coefficient of F1 Microstrip antenna for 433 MHz. Figure 8(b) represents 

simulated reflection coefficient of mF1 Microstrip antenna for 866 MHz. Figure 9(a) shows Input and 

Output waveform of frequency Doubler system using Schottky diode. Figure 9(b) shows output power 

-13.932 dBm of frequency doubler system using Schottky diode.  

 

Figure 8: Reflection coefficient of a) F1 Microstrip antenna for 433 MHz, b) mF1 Microstrip 

antenna for 866 MHz by simulation 

 

Figure 9: a) Input and Output waveform of frequency Doubler system using Schottky diode, b) 

Output power (dBm) of frequency Doubler system using Schottky diode. 



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A prototype of the frequency doubling reflectenna is fabricated and tested to validate the simulation 

results. The practical measures align with the simulation, demonstrating that the reflectenna provides 

enhanced signal strength and frequency doubling capabilities. The measured gain at the doubled 

frequency is approximately 5.1 dBi, with an efficiency of 83% in converting the signal. The proposed 

frequency doubling reflectenna outperforms traditional single-frequency antennas in terms of signal 

strength, bandwidth, and compactness. It also offers better energy efficiency by reducing the need for 

multiple frequency channels in IoT networks, thereby conserving power and enhancing the longevity 

of battery-operated devices. Figure 10(a) shows fabricated reflection coefficient of F1 Microstrip 

antenna for 433 MHz. Figure 10(b) shows fabricated reflection coefficient of mF1 Microstrip antenna 

for 866 MHz. Figure 11(b) shows ESP32 With 866MHz RFM95W Lora Output. Table III represent 

Hardware output power for frequency doubling reflectenna system. 

 

Figure 10: Fabricated reflection coefficient of a) F1 Microstrip antenna for 433 MHz, b) mF1 

Microstrip antenna for 866 MHz 

 

Figure 11: a) hardware fabrication and implementation of frequency multiplying Reflectenna , 

b) ESP32 With 866MHz RFM95W Lora Output 



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Table III: Hardware output power for frequency doubling reflectenna system 

Operating Frequency at 

F1 Antenna  

Distance between 

Tx and Rx 

Operating Frequency 

at mF1 Antenna 

Output 

Power 

433MHz 100cm 866MHz -20dB 

433MHz 200cm 866MHz -28dB 

433MHz 300cm 866MHz -36dB 

433MHz 400cm 866MHz -45dB 

433MHz 500cm 866MHz -55dB 

433MHz 600cm 866MHz -61dB 

433MHz 700cm 866MHz -70dB 

433MHz 800cm 866MHz -78dB 

433MHz 900cm 866MHz -86dB 

433MHz 1000cm 866MHz -89dB 

 

5. Conclusion 

This paper describes the design, analysis, and implementation of a compact planar frequency doubling 

reflectenna for IoT sensor networks. The proposed reflectenna achieves efficient signal conversion, 

broad bandwidth, and directional radiation, making it an ideal candidate for future IoT communication 

systems. The integration of frequency doubling with a compact reflectenna design offers a significant 

advancement in antenna technology, improving energy efficiency and communication range in IoT 

networks. The gain of F1 antenna is 3.5 dBi and gain of mF1 antenna is 5.10dBi. Output power for 

frequency doubling reflectenna system observed -20dB, -89dB for distance between Tx and Rx at 100 

cm, 1000cm respectively. Future work will focus on further optimization of the reflectenna design and 

the exploration of additional nonlinear materials to enhance the overall performance. Further 

integration of the reflectenna with practical IoT sensor nodes and real-world network deployment to 

validate its performance in dynamic environments. Exploring methods to reduce the size further while 

maintaining performance, making the antenna more suitable for ultra-compact IoT devices. 

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