Design of 60 GHz CMOS on-chip dipole antenna with 50 % radiation efficiency by helium-3 ion irradiation

Abstract

In this paper, a 60 GHz CMOS on-chip dipole antenna with helium-3 ion irradiated silicon substrate is designed using knowledge of electromagnetic simulation modeling. Rectangular region with 500 um x 1000 um around the dipole is irradiated by helium-3 ion and conductivity is reduced to 0.01 S/m (1 k Ohm cm). The width of dipole section is wide for broad bandwidth and reduction of conductor loss. There are a taper section and stub for impedance matching. A backing metal reduces back radiation. At 62 GHz, the calculated reflection, radiation efficiency and gain are -15 dB, 48 % and 2.7 dBi, respectively.

The Potentials, Challenges, and Future Directions of On-Chip-Antennas for Emerging Wireless Applications—A Comprehensive Survey

“…In this method, the selective Si substrate near the AoC is irradiated with the Helium-3 Ion Irradiation method in order to decrease its conductivity which in turn boosts the AoC's performance. The employment of this method in [172] for a 60 GHz AoC enhances the radiation efficiency by 43 %. In [173], the use of this method with a vertical reflector for a 140 GHz AoC resulted in a gain rise of 5 dBi.…”

Performance-Issues-Mitigation-Techniques for On-Chip-Antennas – Recent Developments in RF, MM-Wave, and Thz Bands With Future Directions

“…In particular, SoC mitigates major issues associated with SiP [1], [14]- [18], which originate mainly because of the use of bond wires in SiP based systems. Some of such issues include: loss [19], radiation leakage, unintended parasitics, difficulty in realizing and modelling of bond wires [1], [20]- [25], unreliability [22], significant degradation in system's performance at Millimeter-Wave (MM-Wave) frequencies [25], and fabrication tolerance [2]. The inductance of the bond wire and capacitance of the bond pads form a bandpass filter which limit the systems' bandwidth.…”

“…First, the antenna size is compact at these frequencies because of the smaller form-factor [21]. Second, Si based CMOS technologies, the preferred choice for AoC design, haves proved their potential for MM-Wave applications with the innovative developments [15], [20], [21], [23], [32] and transition frequency (f t ) and unity-power-gain frequency (f max ) of Si based transistors have now surpassed 300 GHz. Several MM-Wave frequency bands find their use in a plethora of different valuable applications.…”

“…gain and radiation efficiency in comparison with the off-chip antennas because of the reasons stated in the following paragraph. CMOS has achieved the status of the mainstream IC technology for MM-Wave and THz wireless SoC applications and is preferred due to its low-cost, low-power, and better high-frequency performance based benefits [2], [20]- [23], [31], [32], [34], [41], [44], [47] along with the BiCMOS technology [23], [38]. Moreover, Si based technologies have got remarkable improvements in terms of f t and f max values as a result of tremendous scaling and their f max has now reached 570 GHz [48].…”

“…Hence, these values degrade the gain, directivity, and radiation efficiency (i.e. performance) of AoC and thus make CMOS substrate a lossy one for AoC design [1], [2], [14], [15], [17], [20]- [22], [24], [25], [29], [31], [32], [35], [42], [47]. This, thus, dictates the need for innovative performance-issues-mitigation-techniques for AoCs.…”