# Designed on 0.18 um CMOS Process Small Size Broadband Millimeter Wave Chip Antenna
###### Abstract  
This paper proposes a small-size broadband triangular monopole chip antenna for millimeter wave band applications. Process using 0.18 um CMOS process and antenna design using Met-al_6. Triangular patch design and feed line length analysis to achieve a better reflection coefficient and also dig three circular slots at the grounding point to achieve better impedance matching. The operating frequency of the chip antenna is 62-100 GHz below the reflection coefficient \(-10\) dB standard, with a fractional bandwidth of 54%. The maximum gain is \(-0.4\) dBi at 64 GHz. The efficiency is 40.9%. The overall chip size is \(1.2\times 1.2\) (mm\({}^{2}\)). After measurement and verification, the proposed antenna reflection coefficient is similar to the simulation trend and has better resonance. The chip antenna frequency range proposed in this article covers the 5G NR FR2 frequency band. The proposed chip antenna can be applied in related fields such as the Internet of Things, Industry 4.0, and biomedical electronics. 5G; millimeter wave; chip antenna; CMOS +
Footnote †: journal: Accepted: 24 April 2023  
square millimeters of wafer and the precision of manufacturing technology is becoming increasingly mature [10]. Due to the improvement in the high-frequency characteristics of chip antennas through scaling, complementary metal oxide semiconductors (CMOS) have become a viable manufacturing method for chip antennas and can integrate a complete chip antenna system on a single chip through CMOS processes, further enhancing the competitiveness of the system [11; 12]. However, the radiation efficiency and performance of chip antennas are still their disadvantages. In typical process of CMOS, the low resistivity and high dielectric coefficient of the silicon substrate will seriously cause the loss of the antenna and the silicon substrate will absorb most of electromagnetic waves, greatly reducing the radiation efficiency of the antenna [13]. However, compared to traditional antenna systems, chip antenna systems still have higher bandwidth, better integration advantages, and lower power consumption performance. In addition, as the most critical part of the system, the chip antenna eliminates parasitic effects and uncertainties on the circuit caused by additional connections. It can be directly connected to the circuit without requiring additional matching networks, providing designers with a more flexible design approach and facilitating chip layout [14; 15]. Such a process has been applied in the frequency band of novel communication applications, such as millimeter wave and terahertz. The emergence of chip antennas has brought enormous potential to communication technology, playing an important role in the future Internet of Things [16; 17]. In recent years, there has been extensive research in the field of millimeter wave chips, with different orientations and implementations. For example, resonance analysis [18; 19; 20; 21], the introduction of artificial magnetic conductors [22; 23], the design of integration with printed circuit boards [24; 25], the design of integrated circuits [26], and miniaturization [27]. The influence of the number of twists and turns of a monopole antenna on the operating frequency is shown through simulation results. In reference [18], resonance is achieved at 28 GHz and 60 GHz, achieving the goal of dual frequency. In addition, considering the chip layout, a packaging substrate was selected and placed below the silicon substrate to generate constructive radiation at two frequencies, enhancing antenna gain and efficiency. Reference [19], coupled the feed antenna by adding a square resonant ring, which improved the gain of 7 dBi at 85 GHz and measured a maximum gain of 1.61 dB at 81.5 GHz. Reference [20] analyzed the dual ring antenna and analyzed the influence of dielectric resonator size on the radiation performance and gain of the antenna. In addition, a reflective plate has also been added to the design of the Yagi antenna, which has increased the gain by 0.8 dBi [21].