# Testing and Analysis of MOSFET-Based Absorber Integrated Antenna for 5G/WiMAX/WLAN Applications
## 1 Introduction
The operating frequency had a measured return loss of \(-\)23.42 dB and impedance bandwidth of 90 MHz. [PERSON] et al. [25] created an E-band high-linearity multi-feed antenna LNA front-end with a 45 nm CMOS SOI technology to investigate antenna electronics. This technology supports wireless backhaul and vehicle radar systems. This design takes advantage of antenna noise cancellation and power division to improve the E-band R\({}_{\mathrm{X}}\) Noise Figure (NF) and linearity achievable in silicon front-ends. It was made possible by the high-resistivity silicon substrate employed in it. [PERSON] et al. [26] designed an LNA and dipole antenna. The LNA has a two-stage cascade based on a SiGe:C HBT with a 130 nm wavelength designed for maximum gain. At _80 GHz_, the circuit is designed for vehicle radar applications. The co-integrated LNA measurement results again reveal NFs of 26 dB and 5 dB, respectively, with a 20 mW power consumption, whereas the antenna exhibits a simulated gain of 0 dB. Using 0.13 m SiGe bipolar complementary metal oxide semiconductor (BiCMOS) technology, a W-band power amplifier (PA) with a dipole antenna was co-designed by [PERSON] et al. [27]. The co-design enables direct connections between the PA and the transmitter (Tx) antenna, obviating the need for a matching network between the two blocks and allowing for loss reduction, increased energy efficiency, and downsizing. The monolithic integrated circuit (IC) design and measured results were presented. The maximum output power of the 79 GHz differential PA was 17 dBm. With a 1.8 V supply voltage, the chip consumes 300 mA. In the forward direction, the dipole antenna had a gain of \(-\)14 dBi, while in the backward direction, it had a gain of \(-\)8.5 dBi. A collaborative design strategy for a co-integrated antenna and PA was provided by [PERSON] et al. [28]. This design includes a band-pass RF filter and uses a high-efficiency Doherty PA architecture. After the simulation experiment, a 9% fractional bandwidth (300 MHz) with PAE at the 6 dB output power backed-off level that ranges between 50% and 55% was realized. Similar research work on integrated designs is presented in [29; 30; 31; 32; 33]. However, these designed integrated PA antenna structures do not consider the adverse effects of mismatching between the antenna and the PA used in their co-designmethodology. One of such effects is arching within the PA structure, which results in PA performance degradation. In this present research work, a novel MOSFET-based absorbing antenna was designed with a diode-based quasi-circulator as part of its circuitry. This device can be directly connected to the power amplifier without the need for a matching circuit. This design is aimed to reduce the 50 \(\Omega\) impedance matching limitation on both the PA and the proposed DMS antenna of _[PERSON] and [PERSON]_[34]. On the PA side, the co-design eliminates the challenges of the RF front-end system during matching circuits and eliminates most of the integrated passive parts that serve as a matching circuit. In addition, the rectified reflected power at the MOSFET terminal of the proposed antenna could be amplified and used for low-power operations within the RF front-end system. This paper is organized as follows. Section 2 presents the design of the antenna used for the proposed design. Section 3 shows the design of the MOSFET-based absorber, circulator, and pulse generator used for this antenna. Section 4 presents the design methodology of the antenna. Finally, Section 5 concludes the work and recommends future aspects.