Biquad Antenna Design with Circle Reflectors

ABSTRACT


INTRODUCTION
In this research, we will design a BiQuad antenna using cans as a reflector and driven by copper wire formed by BiQuad as a signal receiver at the 2.4 GHz frequency.This research is useful for providing good access to internet services in Sungai Kupah village to increase creativity.the community, because in that area there is still very little access to the quality of the internet network, one of the factors is the condition of the area where there are still many tall trees, so the signal quality used by electronic devices is obstructed and less stable, another factor is also the BTS tower provider that the community uses is not so much in that area and also the location of the BTS tower is very far from the people's homes there.[12] In this study, there are several variable values that will be analyzed using 2 Tri and Telkomsel providers.The variable values that will be examined are Signal Strength, RSSI, SINR, RSRP, RSRQ, Ping, Upload, Download.The research was conducted for 5 days in the morning and evening, in order to analyze any changes in the values of the variables that have been determined.There are also benefits of this antenna for the people of Sungai Kupah village, namely helping their needs in using internet access, one example is helping people who work as entrepreneurs who usually have to go to the market to deposit their selling products but with the internet they can sell products online.and with a wide reach using applications such as Instagram, Shopee, Whats App, and so on.[8]

METHOD AND THEORETICAL FOUNDATIONS 2.1 Antenna BiQuad
This BiQuad antenna is an antenna consisting of a dipole and a reflector arranged in such a way, in which the dipole uses copper wire in the form of two squares whose corners coincide.
The BiQuad antenna is a double cube-shaped dipole loop wire antenna with a reflector in the form of a flat panel (large flat sheet) with a slightly longer side width than the dipole circuit so that it acts as if it is an infinitely wide field.The location of the reflector is not far from the dipole which aims to reduce backward radiation.With a small distance between the antenna and the reflector, this arrangement also produces a greater gain in the forward radiation.[12]

Radiation Pattern
The antenna radiation pattern is defined as a mathematical function or a graphical representation of the radiation properties of the antenna as a function of the spatial coordinates.Radiation properties include power flux density, radiation intensity, field strength, phase directivity or polarization.The radiation pattern consists of sections called lobes, which are grouped into major and minor (lide and back lobes).As for lobe distribution [3] 1. Main lobe : Part of the radiation area where the antenna radiation direction is maximum.2. Minor lobe: This section states the unwanted radiation area.The level of the minor lobe represents the power density ratio or side lobe level.3. Back lobe: The part of the minor lobe opposite the main lobe 4. Side lobe: Part of the minor lobe adjacent to the main lobe

Parts of the Antenna
Each antenna has its own parameters that will function according to the capacity required by the antenna itself.The following is a schematic of the parameters that will be used on the BiQuad antenna 1. Driven is the supply point of the antenna cable, usually the physical length of the driven is half the wavelength (0.5 λ) of the transmitted or received radio frequency.2. The reflector is the back of the antenna which functions as a signal reflector, with a longer physical length than the driven.the usual length is 0.55 λ (wavelength).[12]

Gain
Gain is an antenna character related to the antenna's ability to direct its signal radiation, or signal reception from a certain direction.Gain is not a quantity that can be measured in common physical units such as watts, ohms or other, but a form of comparison.Therefore, the unit used for gain is decibels.Antenna gain is closely related to directivity and efficiency factors.However, in practice it is very rare that the gain of an antenna is calculated based on its directivity and efficiency, therefore to get the directivity of an antenna is not an easy thing, so in general the maximum gain of an antenna is calculated by comparing it with other antennas which are considered standard antennas ( by measurement method).Antenna gain (Gt) can be calculated by using another antenna as a standard antenna or already having a standard gain (Gs).Where to compare the received power between the standard antenna (Ps) and the antenna to be measured (Pt) from the same transmitting antenna and with the same power.[15]

Modem
Modem is one of the tools used to access the internet.Modem is an abbreviation of the word "Modulator Demodulator".Separately, the modulator-demodulator has different meanings.Modulator can be interpreted as a part whose function is to make an information signal so that it can turn into a carrier signal so that it can be sent.While Demodulator can be interpreted as a part whose function is to separate the information signal from the received carrier signal so that the information obtained can be received properly.From the description above, the modem can be interpreted as hardware that functions as a two-way communication tool.But in general, the term modem is more often used for hardware used for internet communication.[5]

Return Loss
Return Loss is the ratio between the amplitude of the reflected wave and the amplitude of the sent wave.Return loss is described as the increase in the amplitude of the reflected wave compared to the sent wave.Return Loss can occur due to a mismatch between the transmission line and the load input impedance (antenna).[1]

Internet Network
The definition of the internet network in general can be defined as an unlimited computer network that connects one computer user to another computer user, and can connect with computers in an area to regions around the world, where the network has various kinds of information and internet browsing service facilities or surf.This term is better known as "online" on the internet.The Internet is a global system of interconnected computer networks using the standard Internet Protocol Suite (TCP/IP) to serve billions of users worldwide.It is a network of networks consisting of millions of private, public, academic, business, and government networks of local to global scope, which are linked by a code to a broad array of electronic, wireless and optical networking technologies.The Internet can also be defined as the worldwide interconnection of computers and computer networks that facilitate the sharing or exchange of information among users [2]

Research Methodology
In carrying out this final project the research location chosen was in Sungai Kupah Village which has an area of approximately 24.00 Km², has a population of 3,511 located in Sungai Kakap District, Kubu Raya Regency, West Kalimantan.At point 0.019711650429132963, 109.18725627941232led by a village head named Pak Ismail.The choice of this research location was because Sungai Kupah Village could still receive signals but the power level was very low and could not receive internet signals properly.
In this study, BTS distance must be considered because it will affect the results of the data to be retrieved.The BTS distance from the research site is 2.91 Km.For one BTS consisting of 2 providers, namely Tri and Telkomsel, the height of the tower is 72 m, the height of the sectoral antenna provider Tri for each sector is 67 m and the height of the sectoral antenna provider for Telkomsel is 42 m for each sector.

BiQuad Design
The BiQuad antenna is a type of antenna in the form of a combined cube (two quads).Quad antennas are antennas that are rectangular in shape with the same side lengths.The side length of the quad antenna is ¼  (is the wavelength) of the desired antenna frequency.
The length of the driven element of the BiQuad antenna is λ which is the wavelength value.The BiQuad antenna design is obtained from a wavelength of ½ λ which is formed into a folded dipole so that each side is long.For the BiQuad antenna design in this study using the BiQuad calculator software with:

Tin Reflector Design
In designing a can reflector, there are several stages that begin with adjusting the desired working frequency and the size of the driven that will be used.In determining the tools and materials must consider compliance with the specifications of the antenna being designed, this aims to get the desired results.In the manufacturing process, it is possible to modify several predetermined parameters to get the desired results, including by adjusting the focal point, can length and so on which generally can determine the performance of can reflectors which are made by providing a distance of 1.5 cm driven from the reflector backplane .
In the canned reflector design, it is hoped that it can work at a frequency of 2.4 GHz.Furthermore, it will be the value of the frequency parameter in determining other parameters such as the diameter or focal point used at the working frequency so that the 2.4 GHz results obtained from the calculation meet the desired antenna characteristics.[1]

Research Steps
At the research stage the experiment was carried out by going to the village and analyzing signal delays due to several factors and making comparisons after using the antenna.
The research method used is the study of literature and experiments.A literature study was conducted to obtain references regarding theories related to BiQuad antennas.While in the experiment direct measurements were carried out by taking several data samples in Sungai Kupah Village.As for this research, several stages will be carried out so that the research goes according to the procedure.These stages are as follows: 1. Look for data on the location of the nearest BTS towers and the location of the research site by conducting field observations, both sub-districts and residential areas where there is a creative economy and are still reachable by the GSM network but with unstable network quality.2. Make BiQuad schematic designs and techniques for designing canned antennas as a driven reflector formed by BiQuad according to the specifications to be used.3. Retrieve data with predetermined variable values.[7] 4. Make daily data analysis and conclusions from the results of data collection that has been taken.

Data retrieval
In this test, the first thing to do is to prepare the necessary equipment, including smartphones, laptops and modems.
The test steps to be carried out can be explained as follows: 1. Turn on the modem that has been prepared and the antenna is already installed 2. Install the antenna with a height of 10 meters and with a predetermined GSM card.

Results Recording
In recording the results of research conducted using 2 software, namely the application of the modem itself and the Speedtest application.Data collection is carried out when the signal is sent from the BTS to the receiving antenna.The recording of the results of the experiment was carried out for several days with 2 different conditions, namely in the morning and evening by looking for a predetermined variable value.

RESULTS AND DISCUSSION
In the measurement of Tri and Telkomsel providers in Sungai Kupah village, the values of Signal Strength, RSSI, SINR, RSRP, RSRQ, Ping, Upload, Download were obtained.

CONCLUSION
This study designed a signal receiver with a received frequency of 2.4 GHz using tin and copper reflectors in the form of the BiQuad model as a driven.This research was conducted for 5 days in order to analyze any changes in the variable data that had been determined using 2 Tri and Telkomsel providers, these two providers stood on the same tower but there were differences in the height of the sectoral antenna, namely the antenna that functions to transmit signals to be captured by the antenna.For Tri sectoral antenna providers, the antenna is 67 m high from the ground, for Telkomsel providers it is 42 m high from the ground and the antenna is 10 m high from the ground.Based on the research, there are several influences on the quality of the catch, namely from the height of the sectoral antenna, the direction of the antenna which must be facing the BTS tower, the weather, and the research location which is filled with tall coconut trees.
To retrieve variable values from Signal Strength, RSSI, SINR, RSRP, RSRQ, Upload, Download, Ping and retrieve the daily data for 5 research days in the morning and evening.The average value obtained by the Tri provider for 5 days in the morning at Signal Strength -113.

3 .
After the antenna is installed then connect the cable from the antenna to the modem.After that, connect the WiFi from the modem to the smartphone, then open the application to see the values of the data variables that will be retrieved, such as Signal Strength, RSSI, SINR, RSRP, RSRQ by entering the IP address 192.168.8.1 in the browser.4. Open the settings menu and screenshot the RSSI, SINR, RSRP, RSRQ, and Signal Strength values.5. Try again with the specified GSM card.[3]

Table 1
Morning Tri Provider Measurement Results

Table 2
Morning Telkomsel Provider Measurement Results

Table 3
Afternoon Tri Provider Measurement Results