Description:Field of Invention
The present invention relates to the field of wireless communication and antenna technology. More specifically, this invention focuses on the development and application of multi-band monopole antennas integrated with band-pass filters, addressing challenges and optimizing performance in the realm of wireless communication. This antenna facilitates efficient and simultaneous communication over multiple frequency bands.
The objectives of this invention
The invention aims to design a compact reconfigurable multiband antenna which can operate at multiple frequency with high data reliability and with improved efficiency. This antenna reduces the usage of multiple antennas for multiple frequency bands. The compact UWB antenna system with band notch filters is best suitable for wireless handheld devices.
Background of the invention
The invention presented a novel reconfigurable slot antenna for the upper ultra wideband frequency range. The antenna, which is controlled by seven PIN diode switches, can operate in any of eight adjacent sub-bands in the 6.0-10.6 GHz frequency band. The antenna provides a nearly omnidirectional radiation pattern in the horizontal plane at each of its sub-bands, with a predominance of vertical polarization [L. Pazin and Y. Leviatan, IEEE Transactions on Antennas and Propagation, vol. 62, no. 5, pp. 2382-2387, 2014].Reconfigurable antennas are devices that can change their geometry and/or electromagnetic properties on demand to enable different behaviors. Over the last 20 years, numerous approaches to achieving reconfigurability have been studied, primarily mechanical, electrical, optical, and metamaterial methods. This review highlights the most notable works and advancements in this field, with a particular emphasis on antennas with explicit practical applications in the emerging fields of millimeter waves, 5G/6G communications, Internet-of-Things (IoT), high-throughput satellites, and miniaturized systems, among others. The various reconfiguration methods mentioned will be compared, and their advantages and disadvantages were discussed [Ryan J. Beneck, et.al., Progress In Electromagnetics Research, Vol. 171, 89-121, 2021].Recommended a microstrip line fed pentagonal printed ultra-wideband (UWB) monopole antenna with a partial ground plane and triple notches. The realized antenna has an operating bandwidth (VSWR 2) ranging from 3.1 GHz to 12 GHz. In order to introduce triple notches at CBRS (3.5-3.7) GHz, WLAN (5.15-5.725) GHz, and X-band downlink satellite communication (7.25-7.75) GHz frequencies, a novel mushroom-shaped slotted electromagnetic bandgap (EBG) inspired structure is used near the feedline. Current distribution and impedance analysis are used to demonstrate the band notch characteristics. Furthermore, with the exception of the notch frequencies, the structure has stable radiation patterns, gain, and group delay in the UWB range. Finally, the antenna is fabricated, and the measured results agree well with the simulated results [Anumoy Ghosh, et.al., Journal of Electromagnetic Waves and Applications, 33:11, 1391-1405, DOI: 10.1080/09205071.2019.1609377].presented a quad-band notch characteristics ultra-wideband (UWB) antenna for Wi-MAX, L-WLAN, U-WLAN, and C-band applications. The partial ground method has been employed to achieve the initial UWB antenna bandwidth within the 2 to 12.5 GHz frequency band. [Navamani Parthiban, and Mohammed Mohamed Ismail, Progress In Electromagnetics Research C, Vol. 124, 11-22, 2022]. To achieve quad-band notch characteristics, spiral lossy resonator (SLR) slots are loaded into the UWB ground structure. By shedding EM power at the notch frequency, each SLRS circuit is responsible for a single notch characteristic. By inserting four SLR slots circuits into the UWB antenna, a quad-band notch for WiMAX (3.24 to 3.56 GHz), L-WLAN (4.76 to 5.34 GHz), U-WLAN (5.58 to 5.91 GHz), and C-band (7.37 to 7.71 GHz) is accomplished. The antenna is etched on a Rogers RO4003C (3.55mm) substrate with the dimensions of 50X40X1.524 mm3.
Description of Prior Art
The invention relates to a radio antenna, more specifically to an internal multiband antenna for use, For instance, in a portable telecommunication device such as a mobile phone. The invention is particularly directed to an antenna module for a mobile terminal that includes a non-resonant antenna element, two resonant antenna elements each covering at least one of a first, second, third, or fourth frequency band, said two resonant elements are substantially in the same plane and define a planar surface, said two resonant elements are each positioned at a corner of the planar surface, and the non-resonant element is positioned along an edge of the planar surface (US7683839B2). An antenna arrangement for a portable radio communication device that includes an NFC (near field communication) antenna, a BT (Bluetooth) antenna, and an FM (frequency modulation) antenna is an example of an embodiment. The NFC antenna, Bluetooth antenna, and FM antenna are all close to each other and can all be used at the same time. A first decoupling filter feeds the NFC antenna, and a second decoupling filter grounds it (US20120249384A1).The present invention relates to a printed circuit board and an antenna device for a mobile terminal. A first antenna element comprising a first feeding line coupled to a feeding portion of the printed circuit board, a first grounding line coupled to a ground portion of the printed circuit board, and a first antenna pattern emitting a first RF signal; A second antenna element comprising a second feeding line coupled to a feeding portion of the printed circuit board, a second grounding line coupled to a ground portion of the printed circuit board, and a second antenna pattern emitting a second RF signal; A coupling element positioned between the first and second antennas at a predetermined distance;And, in conjunction with the coupling element, a variable circuit element connected between the coupling element and the ground part to form a band cancellation filter(KR20030085000A).
Summary of Invention
Compact monopole antenna with band pass filters for UWB/WLAN applications is designed fabricated and tested. The use of a monopole antenna in the design allows for the implementation of bandpass filters to achieve frequency selectivity. By using band pass filters with the monopole antenna, the antenna can operate in specific frequency bands, which is essential for UWB/WLAN applications that require a wide band antenna. The elliptical ring monopole design is a good choice for wide band applications due to its wide impedance bandwidth and good radiation characteristics. The trapezoidal ground plane is used to improve the antenna's bandwidth and reduce its surface area. The open-loop filter and hairpin coupled filter are used to improve the antenna's selectivity and reduce its interference from other signals in the environment. The antenna's performance was evaluated using the HFSS simulation software, which is a widely used electromagnetic simulation tool for antenna design. The simulation results indicate that the antenna design meets the desired specifications for UWB/WLAN applications. The antenna has a wide bandwidth, good gain, and low return loss. The antenna design is based on the use of five diodes, each of which is used to activate a specific frequency band. The antenna's frequency range is divided into three separate bands: 2-11 GHz, 2.4-2.8 GHz, and 5.6-5.8 GHz. When diode 1 is on, the antenna operates in the frequency range of 2-11 GHz with a gain of 2.7 dB. When diode 2 and 3 are on with an open-loop filter, the antenna operates in a narrowband frequency range of 6.2 GHz -7.2 GHz and 8.6 GHz -9.6 GHzand with a gain of 0.93 dB. When diode 4 and 5 are on with a hairpin coupled filter, the antenna operates in a frequency range of 3.5GHz-4.0GHz, 6GHz-11GHzwith a gain of 3.1 dB. The monopole antenna with band pass filters can also be used in various sensing applications, such as radar, proximity sensing, and imaging. The antenna's ability to detect and transmit signals over a wide frequency range with good gain and performance makes it suitable for applications that require high accuracy and resolution.

Detailed description of the invention
Wireless communication is an essential part of modern life, and the demand for high-speed, reliable connections is growing rapidly. To meet these demands, the development of systems that can incorporate multiple communication standards into a single device is becoming increasingly important. However, designing antennas that can operate at multiple frequency bands is a challenging task due to limited space and other technical constraints. The demand for portable wireless devices has led to the development of systems that incorporate multiple communication standards into a single system. As a result, antennas that can operate at multiple bands are becoming increasingly important, especially in the context of emerging ultra-wide band (UWB) technology UWB antennas are critical components for meeting the low cost, low power, low complexity, and high data rate requirements of wireless connectivity within limited spaces.
Bandpass filters are used to allow only certain frequencies to pass through while rejecting others. They are essential components in wireless communication systems to ensure that the transmitted signals are free from interference and noise. In monopole antennas, bandpass filters are commonly used to limit the frequency range of the antenna and to improve its overall performance. The bandpass filter used in the design of monopole antennas is the 3-hairpin coupled filter. This filter consists of three hairpin resonators that are coupled to each other. The hairpin resonators are designed to resonate at a specific frequency, and the coupling between them is adjusted to achieve the desired frequency response. Lumped RLC components are used in the design of the filter to achieve the desired frequency response. Another type of bandpass filter used in the design is the open-loop filter. This filter uses pin diodes to switch on and off the circuit. When the pin diodes are on, the circuit resonates at a specific frequency, and when they are off, the circuit does not resonate. The UWB frequency band is from 3.1 GHz to 10.6 GHz, and it is used for short-range, high-bandwidth wireless communication systems. The WLAN frequency band is 2.4 GHz and 5.8 GHz, and it is used for local area wireless networks.
The antenna geometry started with an elliptical ring monopole with a trapezoidal ground plane. The elliptical ring monopole is placed above the FR4 epoxy substrate with a relative permittivity of 4.4, a loss tangent of 0.02, and a thickness of 1.6 mm. The trapezoidal ground plane is positioned beneath the substrate, and it is designed to provide good impedance matching and radiation characteristics. The dimensions of the antenna are optimized using HFSS software to achieve the desired multi band operation. The structure of the designed antenna is evolved from elliptical monopole antenna with a radius of “R” and the geometry was optimized to achieve the required antenna structure with The substrate dimensions of 45 mm x 40 mm x 2 mm. Two band pass filters namely open loop filter and hair pin coupled filter are modelled on top of the substrate placed on both sides of the monopole. Then the lumped port is connected to the monopole antenna. And diodes d1, d2, d3, d4, d5 are placed in various positions in the antenna design. These diodes are used as switching circuits to switch between one filter to other.
The S11 parameters of the designed antenna when diode 1 is ON. shows that, the antenna is capable to operate at wide range of frequencies. The wide band capability of the antenna allows it to cover broad frequency range, such as UWB frequency band (2 GHz - 11GHz) and WLAN frequency band (2.4 GHz and 5.8GHz).The feed network of monopole antenna is composed of 50 O micro strip line which allows to realize the desired ultra-wide band response of the antenna. By switching diode 1 on, the 50 O micro strip line RF path will be chosen and diode d1 is placed on the gap made between the 27 mm micro strip line. This will help the antenna to enable the ultra-wide band state. The result meets the 10 dB impedance bandwidth requirement from voluminous range of 2 GHz-11 GHz.
The 2.4 GHz WLAN narrow band response is achieved by adding an open loop filter to the design. The open loop filter is utilized to transform a wide band antenna into a narrow band one. It is designed to attenuate the unwanted frequencies which will help in improving the signal quality and also the antenna performance. It also has the ability to control and shape the frequency response of the antenna. This can be useful for achieving specific requirements such as enhancing selectivity, improving impedance matching at certain frequencies. The simulated results S11 with respect to open loop filter operates at6.2 GHz -7.2GHz and 8.6 GHz -9.6GHz. To switch to the open loop filter, 2 diodes d2 and d3 are placed at the edge of the open loop connecting to the micro strip line of the antenna. To operate the antenna at WI-MAX narrow band state, diodes d2 and d3 are switched ON and other 3 diodes are OFF. Return loss of the antenna with Hair pin coupled filter which helps in achieving 5 GHz narrow band frequency. The hair pin coupled filter is placed to the right of the elliptical monopole antenna. A hair pin coupled filter is a type of resonant filter that uses coupled resonators to achieve desired frequency response characteristics. The multiple resonators in hair pin coupled filter offers improved frequency selectivity. This will allow the filter to efficiently attenuate the signals outside the desired pass band and allows signals within pass band to pass through with minimal loss. 3 hair pin configuration is used, which allows more flexibility in controlling the bandwidth to match desired specifications. To switch to the hair pin coupled filter, 2 diodes d4 and d5 are placed at the edge of the hair pin resonators connecting to the micro strip line of the antenna. To operate the antenna at 3.5GHz-4.0GHz, 6GHz-11GHzC-Bandnarrow band state, diodes d4 and d5 are switched ON and other 3 diodes are OFF.
Brief description of Drawing
In the figures which are illustrated exemplary embodiments of the invention.
Figure 1. Geometry of the UWB antenna: (a) top layer, (b) bottom layer.
Figure 2. Fabricated antenna on FR4 substrate: (a) front view, (b) back view.
Figure 3.Measured and simulated results of the designed antenna when diode 1 is ON.
Figure 4.Measured and simulated results of the designed antenna when diodes 2 and 3 are ON..
Figure 5.Measured and simulated results of the designed antenna when diodes 4 and 5 are ON.
Figure 6. Measured and simulated results of radiation pattern in (a) E-plane (b) H-plane at different frequencies for wide band state
Detailed description of the drawing

Figure 1 shows the designed antenna geometry which was simulated using HFSS 18.2. This antenna was deigned on a FR4 substrate, an elliptical ring structure was designed on top layer of the substrate which is operated in UWB applications. hair pin coupled filter and open loop filterare introduced on to the top layer of the structure which can be used to operate at WI-MAX and C band applications. Ground plane was placed on the bottom layer of the substrate.
Figure 2 depicts the fabricated antenna using printed circuit board technology and PIN diodes are used to gain the frequency reconfigurability based on the pin diode switching conditions this antenna can be used for UWB, WI-MAX and in C band applications. The power supply to the pin diodes is given with the equivalent circuit. SMA connector is used to give the feeding to the antenna.
Figure 3 depicts the measured and simulated S11 parameters of the antenna when diode 1 is ON and remaining diodes are in OFF which shows that the antenna is capable to operate at wide range of frequencies.
Figure 4illustrates the measured and simulated S11 parameters of the antenna when diode d2 and d3are ON and remaining diodes are in OFF state which shows that the antenna is capable to operate at 6.2 GHz -7.2GHz and 8.6 GHz -9.6GHz narrow band range of frequencies.
Figure 5describes the measured and simulated S11 parameters of the antenna when diode d4 and d5 are ON and remaining diodes are in OFF state which shows that the antenna is capable to operate at 3.5GHz-4.0GHz, 6GHz-11GHznarrow band range of frequencies.
Figure 6represents the measured and simulated Radiation pattern of the antenna at different frequencies
4 Claims & 6 Figures , Claims:The scope of the invention is defined by the following claims:

Claims:

1. The antenna is simulated usingAnsoft High Frequency Structural Simulator HFSS.18.2 of following steps:
To observe the effect on elliptical ring UWB antenna with open-loop filter and hair pin coupled filters.
(a) Designed The elliptical ring monopole design which is a good choice for wide band applications due to its wide impedance bandwidth and good radiation characteristics.
(b) The trapezoidal ground plane is used to improve the antenna's bandwidth and reduce its surface area.
(c) Designed monopole antenna with band pass filters for UWB/WLAN applications.

2. The Designed is fabricated using printed circuit board technology and tested using network analyzer for S11 parameters and anechoic chamber for radiation pattern at different frequencies.
3. Reconfigurability achieved by using PIN diodes based on the pin diode switching the antenna can operates at multiple frequency bands. This makes the antenna more versatile for wireless communication.
4. Narrow Frequency bands are selectively filtered within UWB frequency range using various kinds of bandpass filters.