High gain omnidirectional antenna future development trends and technical challenges

　　Future Development Trends and Technical Challenges of High-Gain Omnidirectional Antennas

　　Abstract: This paper deeply explores the development trends and technical challenges of high-gain omnidirectional antennas in the future communication field. By combing the current research progress and application status, this paper analyzes its development trends in high-frequency band expansion, intelligent upgrading, materials and structural innovation driven by the needs of 5G, Internet of Things, satellite communications and other scenarios. At the same time, the technical bottlenecks that restrict its further development are analyzed from the perspectives of thermal management, cost control, electromagnetic compatibility, etc., providing a reference for subsequent research and industrial development.

　　I. Introduction

　　In wireless communication systems, antennas are key components for realizing the mutual conversion between electromagnetic waves and electrical signals, and their performance directly affects the communication quality and coverage. High-gain omnidirectional antennas are widely used in many fields because they can radiate signals uniformly within a 360° range in the horizontal direction and have high gain. With the large-scale deployment of 5G networks, the explosive growth of Internet of Things (IoT) devices, and the rise of emerging technologies such as satellite communications, higher requirements are placed on the performance of high-gain omnidirectional antennas, prompting them to continue to innovate and evolve at the technical level.

　　2. Overview of the development status of high-gain omnidirectional antennas

　　2.1 Technical principles and core characteristics

　　High-gain omnidirectional antennas achieve effective signal enhancement in the omnidirectional range by optimizing antenna structure, adopting multi-unit arrays, and phase control. Taking the common dipole antenna array as an example, by reasonably setting the unit spacing and feeding phase, the radiation intensity in the vertical direction can be improved while maintaining the omnidirectional radiation characteristics, thereby increasing the gain. Its core characteristics include wideband characteristics, which can adapt to the needs of various communication frequency bands; high gain characteristics, which effectively improve the signal transmission distance and stability; and good omnidirectional coverage characteristics, ensuring reliable communication in all directions.

　　2.2 Current status of application fields

　　In the field of 5G communications, high-gain omnidirectional antennas are widely used in micro base stations and macro base stations. According to the 2023 Communications Industry Statistical Bulletin of the Ministry of Industry and Information Technology, the total number of 5G base stations in China has reached 3.189 million, of which micro base stations using high-gain omnidirectional antennas will account for 28% in 2023, up from 12% in 2021, and are expected to exceed 45% in 2025. In the field of the Internet of Things, with the rapid growth in the number of device connections, miniaturized, high-gain omnidirectional antennas have become the key to achieving stable communication between devices. For example, the NBIoT omnidirectional antenna module launched by Quectel has been reduced in size to 15×15×2mm, with a gain value of 3dBi, and a market share of more than 45% in the field of smart meters. In terms of satellite communications, the Ka-band (26.5-40GHz) omnidirectional phased array antenna developed by the Aerospace Science and Technology Group uses a 256-unit array design to achieve 360° continuous coverage in azimuth in low-orbit satellite mobile terminals, and the measured Eb/N0 value is 4.2dB higher than the traditional solution.

　　3. Future development trends

　　3.1 High-frequency and broadband development trends

　　3.1.1 Acceleration of commercial use of millimeter-wave bands

　　With the in-depth development of 5G networks, the commercialization of millimeter-wave bands (24.25 - 52.6GHz) is accelerating. This band has rich spectrum resources and high-speed data transmission capabilities, which can meet application scenarios such as high-definition video transmission and industrial AR/VR that have stringent requirements on bandwidth and latency. In the millimeter-wave band, the antenna array scale has been upgraded from 64 units to 256 units. For example, Huawei's MetaAAU 3.0 solution uses metamaterial lens technology to increase the gain to 12dBi while reducing power consumption by 30%. However, the millimeter-wave band has large signal propagation loss and extremely high requirements for antenna performance, and key issues such as thermal management need to be resolved. Leading companies are using microchannel heat dissipation technology to reduce the operating temperature by 15°C, and it is expected to achieve a commercial breakthrough in the 28GHz band in 2025.

　　3.1.2 Terahertz band exploration and 6G pre-research

　　The terahertz band (0.1 - 10THz) has become the focus of 6G communication technology pre-research due to its higher frequency and bandwidth potential. The fourth-generation products that will be mass-produced in 2024 have begun to integrate terahertz communication modules to support 6G technology exploration. Terahertz band high-gain omnidirectional antennas need to make breakthroughs in metamaterial applications and nano-manufacturing processes to achieve efficient radiation and reception of higher frequency band signals to meet future ultra-high-speed and large-capacity communication needs.

　　3.2 Improvement of intelligence and adaptive capabilities

　　3.2.1 Development of AI-driven beamforming technology

　　The integration of intelligent beamforming technology and multiple-input multiple-output (MIMO) technology enables the antenna system to adjust the beam direction and gain in real time according to the surrounding electromagnetic environment. AI algorithms can analyze and process massive amounts of channel state information to achieve precise beam pointing and optimization. Test data shows that this technology can improve the signal coverage efficiency of antenna systems in complex electromagnetic environments by more than 30%. For example, Huawei's CloudAIR 3.0 solution realizes dynamic optimization of antenna parameters in the cloud, and the beam switching delay is shortened from 20ms to 5ms.

　　3.2.2 Widespread application of adaptive antenna system (AAS)

　　Adaptive antenna system can automatically adjust antenna radiation pattern and parameters according to communication needs and environmental changes. The penetration rate of AI-driven AAS is expected to increase from 15% to 40% in 2025. In high-rise buildings and densely populated areas, AAS can optimize the signal coverage quality of 5G base stations by dynamically adjusting beams. The actual signal strength of buildings above 30 floors has increased by 40%, effectively solving the problems of signal shielding and interference.

　　3.3 Trends in material innovation and structural innovation

　　3.3.1 Application progress of new materials

　　New materials play a key role in improving antenna performance. The penetration rate of gallium nitride (GaN) power amplifier devices will increase from 18% in 2022 to 34% in 2023, pushing antenna efficiency to over 45%. The liquid crystal polymer (LCP) substrate improves the stability of the antenna dielectric constant to ±0.15 (25 - 85℃) and reduces the insertion loss by 0.3dB. The liquid crystal polymer-based substrate material developed by Southeast University effectively improves the performance stability of the antenna under wide temperature environments. The application of metamaterials such as near-zero refractive index materials (NZIM) can increase the antenna gain by 0.6 - 2dB, while achieving a low-profile design (λ/30), which is suitable for wearable devices and vehicle-mounted scenarios.

　　3.3.2 Three-dimensional packaging and array structure optimization

　　Three-dimensional packaging technology compresses the antenna unit spacing to 0.2λ, greatly improving the array integration and signal processing capabilities. The array scale is expanded to 1024 units, enabling the antenna to achieve more precise beam control and higher gain. The open architecture led by the ORAN Alliance has reduced the cost of antenna units by 28%. The cost of large-scale commercial use is expected to drop to 1,200 yuan per unit in 2024, which has promoted cost optimization and technology popularization in the antenna industry.

　　3.4 Scenario-based applications and multi-technology integration trends

　　3.4.1 The driving role of satellite communications and low-orbit constellations

　　The rise of low-orbit satellite communications has brought new opportunities for high-gain omnidirectional antennas. It is expected that the domestic satellite Internet terminal antenna market will exceed 5 billion yuan in 2025. The integration of low-orbit satellites and ground communication systems requires antennas to have high reliability and omnidirectional coverage in complex orbital environments. For example, the Ka-band omnidirectional phased array antenna developed by the Aerospace Science and Technology Group provides stable communication guarantees for low-orbit satellite mobile terminals.

　　3.4.2 Demand driven by the Internet of Things and intelligent transportation

　　The number of connected IoT devices is expected to exceed 2.5 billion in 2025, and there is a strong demand for miniaturized, low-power, high-gain omnidirectional antennas. In the field of intelligent transportation, the on-board 5G V2X antenna integrates GPS/Beidou dual-mode positioning, supports wide temperature operation from -40℃ to +85℃, and the installed volume will exceed 1.2 million units in 2023. The communication between vehicles and infrastructure and between vehicles in the intelligent transportation system relies on high-gain omnidirectional antennas to achieve reliable and real-time data transmission.

　　3.5 Green energy and sustainable development trends

　　3.5.1 High-efficiency design reduces energy consumption

　　Through AI algorithms, antenna units can be activated on demand, and power consumption can be reduced to 35% of full load during low-load periods, reducing energy consumption. For example, some smart antenna systems can dynamically adjust the antenna working mode according to network traffic to avoid unnecessary energy waste, which is in line with the concept of green communication.

　　3.5.2 Recyclable materials and environmentally friendly design

　　Use degradable substrate materials (such as bio-based polymers) and modular design to reduce the impact of electronic waste on the environment and comply with environmental standards such as EU RoHS. Considering the recyclability and environmental friendliness of materials during the product design phase is an important direction for the development of high-gain omnidirectional antennas in the future, which will help achieve sustainable development of the industry.

　　IV. Technical Challenges

　　4.1 High-frequency thermal management and reliability problems

　　4.1.1 Challenges of heat dissipation in the millimeter-wave band

　　In the millimeter-wave band, a large amount of heat is generated when the antenna is running at high power, and the traditional metal radiator has low heat dissipation efficiency and large volume. Although microfluidic heat dissipation technology can effectively reduce the temperature, the manufacturing process is complex and the problems of fluid sealing and long-term stability need to be solved. For example, in some millimeter-wave base station antennas, the sealing failure of the microfluidic heat dissipation system causes the coolant to leak, affecting the normal operation of the antenna.

　　4.1.2 Material weather resistance problems

　　In outdoor applications, environmental factors such as high temperature, humidity, and salt spray can easily cause antenna materials to age and affect performance. For example, the reliability of GaN devices in high temperature and high humidity environments needs to be improved by optimizing packaging technology to ensure long-term stable operation in harsh environments.

　　4.2 Cost control and obstacles to large-scale production

　　4.2.1 High array costs

　　Millimeter wave antenna arrays with more than 256 units require a large number of RF front-end chips (such as T/R modules), resulting in a single base station antenna cost of more than 100,000 yuan. Although open architecture can reduce unit costs, the compatibility issues of multiple manufacturers' products are prominent, which increases the difficulty and cost of system integration.

　　4.2.2 Strict process accuracy requirements

　　The subwavelength structure of metamaterial antennas (such as NZIM unit gaps must be controlled within 100 microns) has extremely high requirements for lithography and etching processes, and it is difficult to improve the yield, which restricts large-scale production and market promotion.

　　4.3 Electromagnetic compatibility and standardization dilemma

　　4.3.1 Multi-system interference suppression problem

　　Multiple standard signals such as 5G, Internet of Things, and satellite communications coexist, and antennas need to have the ability to resist co-frequency interference. In intelligent transportation scenarios, vehicle antennas need to process V2X, GPS, and 5G signals at the same time, and there are challenges in optimizing signal reception through filtering and beamforming technology.

　　4.3.2 Complexity caused by differences in international standards

　　Different countries and regions have different requirements for electromagnetic radiation (such as FCC, CE certification) and frequency band allocation. Antenna design needs to take into account global compliance, which increases the complexity and cost of R&D. For example, in some European countries, the restriction standards on antenna radiation power density are different from those in the United States, and companies need to customize designs for different markets.

　　4.4 Technical bottlenecks of omnidirectionality and gain balance

　　4.4.1 Difficulty in optimizing radiation patterns

　　Traditional omnidirectional antennas have low vertical gain. When the vertical gain is improved through multi-unit arrays and phase control, it is easy to introduce the problem of non-circularity of the radiation pattern. Dynamic calibration of the radiation pattern through metamaterials or AI algorithms is difficult and costly to implement.

　　4.4.2 Multi-user fairness issues

　　In dense scenarios, high-gain omnidirectional antennas may cause signals to focus on specific areas, and some users have weak signals. In order to achieve dynamic resource allocation by combining distributed antenna systems (DAS) or edge computing, the problems of increased system complexity and rising costs need to be solved.

　　4.5 6G pre-research and technology iteration risks

　　4.5.1 Uncertainty of technical routes

　　6G may adopt terahertz frequency band and intelligent metasurface (RIS) technology, and the existing high-gain omnidirectional antenna design concept faces challenges. Enterprises need to establish a dynamic R&D system and plan new materials and architecture research in advance to cope with technological changes.

　　4.5.2 Patent barriers restrict development

　　Heading companies have a large number of core patents in the fields of metamaterials and beamforming, and innovation of small and medium-sized enterprises is limited. It is necessary to break through the technical blockade through cooperative R&D, patent cross-licensing, etc., and promote the overall development of the industry.

　　V. Conclusion

　　High-gain omnidirectional antennas have broad prospects in the future communication field, and show clear development trends in high-frequency band expansion, intelligent upgrading, material innovation and scenario-based applications. However, to achieve its further development and wide application, it is necessary to overcome many technical challenges such as thermal management, cost control, and electromagnetic compatibility. Industry, academia and research need to strengthen cooperation, increase R&D investment, and work together to promote technological innovation and standard setting in order to promote the continuous advancement of high-gain omnidirectional antenna technology and meet the diversified and high-performance needs of future communications.