From the perspective of energy conversion, unlocking the evolution code of antennas WWW.WHWIRELESS.COM Estimated 15minutes to finish reading In the vast system of wireless communication, antennas play a key role. Essentially, they are a very special type of energy converter that can achieve energy conversion between guided waves and free space waves. This conversion process is of paramount importance in the transmission and reception stages of communication signals. When in the signal transmission state, the high-frequency current from the transmitter is transmitted along the transmission line to the antenna. At this moment, the antenna acts like a magical wizard, skillfully converting the energy in the form of guided waves (high-frequency current) into free space waves, which we commonly refer to as electromagnetic waves, and then radiating them into the surrounding space. For example, in common mobile phone communication, the internal circuits of the phone generate high-frequency current signals, which are transmitted to the phone's antenna. The antenna then converts these signals into electromagnetic waves and emits them, establishing a communication connection with the base station to achieve information transmission. In the signal reception phase, the antenna's work is the reverse of the above process. When electromagnetic waves propagating in space reach the antenna, it sensitively captures these electromagnetic waves and converts the energy they contain into high-frequency current, which is the conversion from free space waves to guided waves. This high-frequency current is then transmitted through the transmission line to the receiver for subsequent signal processing and information extraction. For example, the television antenna in our home can receive electromagnetic waves emitted by television stations and convert them into electrical signals, which are transmitted to the television, allowing us to watch a variety of television programs. Early Exploration: The Prototype of Antennas and Initial Energy Conversion In the 19th century, the field of electromagnetism witnessed significant theoretical breakthroughs. James Clerk Maxwell proposed the famous Maxwell equations, theoretically predicting the existence of electromagnetic waves and laying a solid theoretical foundation for the birth of antennas. In 1887, German physicist Heinrich Hertz conducted a series of pioneering experiments to verify Maxwell's predictions. He designed and manufactured the world's first antenna system, consisting of two metal rods about 30 centimeters long, with the ends connected to two metal plates of 40 square centimeters. Electromagnetic waves were excited through spark discharges between the metal balls; the receiving antenna was a single-loop metal square ring antenna, which indicated that a signal was received when sparks appeared between the endpoints of the ring. Hertz's experiment not only successfully confirmed the existence of electromagnetic waves b...

Exploring the 700MHz Band:Why It Is Regarded as the"Golden"Frequency in the Communication World https://www.whwireless.com/ Estimated 15minutes to finish reading In today's era of rapidly developing communication technology,frequency bands are like"magic keys"in the world of communication,unlocking different"treasures"of communication.Among them,the 700MHz band is particularly favored and is hailed as the"golden"frequency band.What are the secrets behind this?Let's delve into it together.  Superior Propagation Characteristics:Signals Travel Unimpeded Just as marathon runners experience fatigue,signals also attenuate during propagation.The 700MHz band can be regarded as a"long-distance runner"in the communication world.According to the free-space propagation loss formula,the lower the frequency,the smaller the propagation loss.Compared to higher-frequency bands such as 2.6GHz and 3.5GHz,the 700MHz band experiences much less signal attenuation.This means it can cover longer distances and deliver signals stably to their destinations.Whether in remote mountainous areas or vast rural regions,it can easily provide coverage. Strong Diffraction:Overcoming Obstacles When signals encounter obstacles like high-rise buildings or towering mountains,high-frequency signals often get blocked.However,the 700MHz band,with its longer wavelength,demonstrates strong diffraction capabilities.Like a nimble dancer,it can cleverly bypass obstacles and continue on its way.This characteristic ensures stable signal propagation in complex urban environments,preventing communication signals from being easily"intercepted"by obstacles. Deep Penetration:Full Signal Strength Indoors Indoor signal weakness is a common problem.However,the 700MHz band has excellent penetration capabilities,allowing it to easily pass through building walls and reach every corner of the interior.This means that indoors,we can enjoy smooth communication services without worrying about weak signals.Whether streaming videos,playing games,or making video calls,the signal remains strong. Cost-Effective Network Deployment In communication network construction,base stations are the key"signal fortresses."The low propagation loss and wide coverage of the 700MHz band bring significant cost advantages for network deployment.Calculations show that with the 700MHz band,building 450,000 to 500,000 base stations is sufficient to cover the entire country.If other frequency bands were used,achieving the same coverage would require a much larger number of base stations.This would not only significantly increase construction costs but also lead to higher maintenance and management expenses.The 700MHz band,with its advantages,greatly reduces the burden on operators,making communication network construction more economical and efficient. Wide-Area Coverage:A Boon for Remote Areas  In rural and mountainous regions with vast areas and sparse populations,as well as high-speed scenarios like high-speed rail and hig...

Antenna Popular Science - Operating Bandwidth https://www.whwireless.com/ Estimated 15minutes to finish reading I. Definition and Classification 1. Definition: Antenna bandwidth generally refers to the frequency range corresponding to when a certain parameter of the antenna (such as gain, voltage standing wave ratio, etc.) meets specific requirements. 2. Classification Absolute Bandwidth: It is the actual frequency range within which the antenna can operate. The calculation formula is Δf = fmax - fmin, where fmax is the highest frequency at which the antenna can operate, and fmin is the lowest frequency at which the antenna can operate. Relative Bandwidth**: It is expressed as the ratio of the difference between the upper and lower limit frequencies to the center frequency. The calculation formula is Relative Bandwidth = (f_high - f_low) / f_center. II. Influencing Factors and Representation Methods 1. Influencing Factors: The bandwidth of an antenna is affected by various factors, including the physical size, shape, material of the antenna, and design objectives. For example, techniques such as using thicker metal wires, metal “wire cages” to approximate even thicker metal wires, and integrating multiple antennas into a single component can all increase the antenna's bandwidth. 2. Representation Methods: Voltage Standing Wave Ratio (VSWR) Condition: Under the condition that the voltage standing wave ratio VSWR ≤ 1.5, the operating frequency band width of the antenna is called the antenna's bandwidth. This is a commonly used definition in mobile communication systems. Gain Drop Condition: The frequency band width within which the antenna gain drops by 3 decibels is also called the antenna's bandwidth. This representation method focuses on the characteristic of the antenna gain changing with frequency. III. Practical Applications and Significance 1. Practical Applications: In communication systems, the selection of antenna bandwidth is crucial for the system's performance. If the antenna bandwidth is too narrow, it may not be able to cover the required communication frequency range, resulting in a decline in communication quality or failure to establish a communication connection. Therefore, when choosing an antenna, comprehensive consideration should be given to factors such as the communication frequency range, bandwidth requirements, and antenna performance of the system. 2. Significance: Antenna bandwidth is one of the important indicators for measuring the performance of an antenna. It determines the radiation and reception capabilities of the antenna at different frequencies and is of great significance for ensuring the stability and reliability of the communication system. Types of Antenna Bandwidth I. Absolute Bandwidth 1. Definition: Absolute bandwidth refers to the actual frequency range within which the antenna can operate, that is, the difference between the highest frequency and the lowest frequency when the antenna's performance indi...

Basic knowledge of antenna measurement https://www.whwireless.com/ Estimated 25minutes to finish reading The basic knowledge of antenna measurement involves multiple aspects, including antenna functions, performance parameters, measurement methods, and testing environments. The following is a detailed explanation of the basic knowledge of antenna measurement: 1、 The function of the antenna Antenna is a key component of wireless communication systems, and its main functions include: Directional radiation or reception of radio wave signals: In the transmitting state, the antenna converts high-frequency electromagnetic energy in the transmission line into electromagnetic waves in free space; In the receiving state, the electromagnetic waves in free space are converted into high-frequency electromagnetic energy in the transmission line. Energy Conversion: Antennas need to efficiently convert the guided wave energy propagated by the feeder system into electromagnetic wave energy, or convert the received electromagnetic wave energy into current signals. • Directionality: Antennas can radiate or receive electromagnetic waves in a directional manner, concentrating them in the desired direction as much as possible. Polarization: The antenna should be able to emit or receive electromagnetic waves of the specified polarization. 2、 Performance parameters of the antenna The performance parameters of an antenna are important indicators for measuring its performance, mainly including: Gain: Refers to the ability of an antenna to amplify the received signal, usually closely related to directionality. Directionality: Describes the radiation power intensity of an antenna in a specific direction relative to its omnidirectional radiation state. Efficiency: includes antenna radiation efficiency and overall efficiency, with the former considering antenna losses and the latter considering overall losses such as conductor and dielectric losses of the antenna. Impedance: The ratio of voltage to current at the antenna input terminal, which is the load of the feeder system and requires good impedance matching with the feeder system. Standing wave ratio (VSWR): reflects the degree of matching between the antenna and the feeder system. Polarization: The polarization method by which an antenna emits or receives electromagnetic waves. Operating Frequency Band: The frequency range within which an antenna can operate normally. 3、 Antenna measurement method The measurement of antenna parameters is usually carried out using instruments such as field strength meters, power meters, impedance meters, or network analyzers, as well as specialized testing equipment such as standard antennas. The measurement methods include: Radiation directional pattern measurement: By using fixed antenna method or rotating antenna method, measure the radiation intensity of the antenna in different directions and draw the radiation directional pattern. Gain measurement: Using the comparison method, comp...