On-chip Antenna Research Articles

On-Chip-Antennas: Next Milestone in the Big World of Small Satellites—A Survey of Potentials, Challenges, and Future Directions

Small satellites have revolutionized the space industry because of their variety of benefits over large satellites. Antennas are one of the key components of the small satellites, whose performance is very crucial for the overall performance of the satellite-based wireless systems. The stringent requirements of modern small satellites, such as the small size and mass, low-power, low-loss, and low-cost dictate the need for the alternative antenna technologies, as the traditionally employed off-chip antenna technology faces a number of severe constraints to meet this set of requirements. On-chip-antennas (OCAs) are one of such promising choices, which are more favorable than off-chip antennas in this respect. This article, therefore, presents a comprehensive survey of OCA capabilities for modern small satellite (micro-satellite, mini-satellite, nano-satellite, pico-satellite, femto-satellite, cubsat) applications for the first time. A number of key challenges posed by OCAs for small satellite applications are investigated and discussed analytically. The article also delineates a few future perspectives in this regard. This article will not only highlight a number of novel research opportunities for the relevant researchers but also urge them to propose innovative solutions for OCA design challenges for these applications.

A Review of Design and Integration Technologies for D-Band Antennas

This article reviews the current state-of-the-art of millimeter-wave (mm-wave) antennas for communication and sensing applications in the D-band between 110 and 170 GHz. The most popular design techniques, including Antenna-on-Board (AoB), slotted waveguides, Antenna-in-Package (AiP) and Antenna-on-Chip (AoC), are described using relevant examples from scientific literature. Potential benefits and limitations of integration technologies, such as specialized packaging, chip post-processing steps and interconnects, are listed as well. The reported performances of all listed designs are compared against each other, taking the antenna size relative to operating frequency into account. This novel comparison indicates that small-scale integrated AiP and AoC designs can achieve competitive performance levels with short and low-loss interconnects.

Broadband Sensing Around 1 THz Via a Novel Biquad-Antenna-Coupled Low-NEP Detector in CMOS

We report on the design and characterization of a novel backside-radiating antenna-coupled direct terahertz detector fabricated in 65 nm CMOS technology. The novelty of the design lies in the low-metal coverage of the biquad antenna geometry, which adapts well to the particular challenging conditions of on-chip antenna integration in silicon and allows optimization for a versatility of operation conditions. The biquad antenna was modified here to achieve wideband radiation and matching to a gate-coupled single-finger field-effect transistor with ac open condition at the drain terminal. The successful detector performance was the result of a careful treatment of transistor, antenna, and optics from a codesign perspective, since the beginning of the design. This included the frequency-dependent complex impedance for optimum matching, the technology restrictions to ensure proper chip fabrication, and the overall detection efficiency after backing the device with a silicon lens. Calibrated detector measurements for 7777 Hz modulation frequency yielded minimum optical noise-equivalent-power (NEP) of 25 pW/ $\sqrt{\,}$ Hz at 1 THz, with NEP values below 50 pW/ $\sqrt{\,}$ Hz in the 0.84–1.29 THz frequency range. These figures achieve state-of-the-art of wideband CMOS-based detectors and are only a factor of ${{\sim}2}$ inferior to the best reported narrowband devices close to 1 THz.

Equivalent Circuit Model Separating Dissipative and Radiative Losses for the Systematic Design of Efficient Microstrip-Based On-Chip Antennas

This article presents a comprehensive method to efficiently design capacitively enhanced resonant on-chip antennas using an equivalent circuit (EC) model instead of computationally demanding full-wave simulations. To systemize the design process by predicting the radiation efficiency, the input impedance, the current and voltage distributions, and the radiation pattern of the antenna based on an EC, a method to extract both dissipation and radiation mechanisms from full-wave simulation data is described and carried out. Based on this separation of loss mechanisms, an EC-based antenna optimization with respect to the radiation efficiency is conceivably possible. Additional to the EC, which enables this efficient antenna optimization and increases the physical insight in the radiation mechanism, an analytical estimation of key antenna parameters, as the resonant length, is presented. The results from the analytical calculations and the antenna parameters calculated using the EC model are compared with full-wave FDTD simulations and used to discuss the capabilities and limitations of the EC model. Finally, an on-chip antenna of the considered type operating at 290-300 GHz and manufactured with silicon-germanium technology is used to verify the full-wave antenna simulations and the presented approach in general.

Monostatic and Bistatic G-Band BiCMOS Radar Transceivers With On-Chip Antennas and Tunable TX-to-RX Leakage Cancellation

This article presents $G$ -band monostatic and bistatic radar transceivers (TRX) incorporating on-chip antennas for short-range high-precision applications. The circuits were fabricated using a silicon–germanium (SiGe) BiCMOS technology offering heterojunction bipolar transistors (HBTs) with $\bf {f}_{\mathbf {T}}/\bf {f}_{\mathbf {MAX}}$ of 300/500 GHz. The monostatic TRX implements a tunable leakage canceller (LC) for enhanced transmitter (TX)-to-receiver (RX) leakage compensation and hence improved detectability of weakly reflecting near targets. A standalone monostatic TRX characterized at on-wafer level achieves 4-dBm maximum output power ( $\bf {P}_{\mathbf {TX}}$ ) and 19-dB peak conversion gain ( $\bf {G}_{\mathbf {RX}}$ ) with 3-dB bandwidths of 18 and 17GHz for the TX and the RX, respectively. The bistatic version reaches $\bf {P}_{\mathbf {TX}}$ of 13 dBm and $\bf {G}_{\mathbf {RX}}$ of 24 dB expanding the 3-dB bandwidths to 32 and 34 GHz for the TX and RX, respectively. A double-folded dipole antenna providing 5-dBi gain at 170 GHz was implemented using localized backside etching (LBE) and integrated with the transceivers. A frequency-modulated continuous-wave (FMCW) radar demonstrator incorporating an external phase-locked loop (PLL) was built to evaluate both TRXs and tunable leakage cancellation feature available in the monostatic variant. The maximum equivalent isotropic radiated power ( $\bf {EIRP}$ ), including on-chip antennas, is 8 and 18 dBm for the monostatic and bistatic TRX, respectively. The radars support sweep bandwidth up to 20 GHz reaching 2.1 cm spatial resolution. For a target at 1 m distance the measured ranging precision is $105~\mu \text{m}$ and $13~\mu \text{m}$ for monostatic and bistatic TRX, accordingly. Activation of leakage cancellation effectively suppresses close-in noise and extends the minimum detectable range remarkably.

On-Chip Antenna Design Using the Concepts of Metamaterial and SIW Principles Applicable to Terahertz Integrated Circuits Operating over 0.6–0.622 THz

This research work presents the investigation of realizing an on-chip antenna based on the metamaterial concept, which is working over the terahertz (THz) band for applications in integrated circuits. The proposed on-chip antenna is constructed of five stacked layers of polyimide and aluminum as top and bottom substrates, radiation patches, ground plane, and feed line. The four square-shaped radiation patches are implemented on the 50 μ m top-polyimide substrate, and the feed line is realized on the 50 μ m bottom-polyimide layer by designing the simple square microstrip lines, which are all connected to each other and then excited by waveguide port. The ground plane including a coupling square slot has sandwiched between the top- and bottom-polyimide layers. The coupling square slot etched on the ground plane is exactly placed under the patch to optimum transfer the electromagnetic signal from the bottom feed line to the top radiation patch. To achieve high performance parameters without increasing the antenna's physical dimensions, the metamaterial and substrate integrated waveguide properties have been applied to the antenna structure by implementing linear tapered slots on the patch top surfaces and metallic via holes throughout the middle ground plane connecting top and bottom substrates to each other. The slots play the role of series left-handed (LH) capacitors (CL) and the via holes act as shunt LH inductors (LL). The overall dimension of the proposed metamaterial-based on-chip antenna is 1000 × 1000 × 100 μm3. This antenna can cover the frequency band from 0.6 THz to 0.622 THz, which is equal to 20 GHz bandwidth. The radiation gain and efficiency across the operating frequency band varies from 1.1 dBi to 1.8 dBi, and from 58% to 60.5%, respectively. The results confirm that the proposed on-chip antenna with compact dimensions, wide bandwidth over the terahertz domain, low profile, cost effective, simple configuration, and easy to manufacture can be potentially appropriate for terahertz integrated circuits.

Multimode W-Band and D-Band MIMO Scalable Radar Platform

This article demonstrates the implementation of 80- and 160-GHz four-channel radar sensors employing the modular scalable platform based on a single relaxed 40-GHz local oscillator and cascadable transceiver chips. The first two channels synthesize $2 \times 2$ multiple-input–multiple-output (MIMO) radar at 80 GHz with onboard $8 \times 1$ patch arrays for enhanced angular resolution, whereas the other two channels employ 160-GHz system-on-chip transceivers with integrated wideband 6-dBi micromachined on-chip antennas for enhanced range resolution. Configurable modulators in each transceiver offer ranging, direction-of-arrival (DoA) estimation, velocity/vibrations measurement, and data communication applications. Frequency-modulated continuous wave (FMCW) is demonstrated with 4-/8-GHz sweep bandwidth at 80/160 GHz corresponding to 3.75-/1.875-cm range resolution. Chirp-sequence FMCW is employed to measure the heartbeat rate of a human, and 78 bpm is measured with 0.06-Hz Doppler resolution. Mechanical vibration rate from a loudspeaker is measured using the CW radar technique, whereas phase-modulated continuous wave is employed for distant selective vibrations measurement. Time-division multiplexing MIMO radar is configured at 80 GHz in a multitarget scenario for DoA estimation, and the targets are distinguished with 25° effective angular resolution. Frequency-division multiplexing MIMO radar technique is demonstrated based on $\Delta \Sigma $ -modulation and binary phase shift keying (BPSK) modulators. Furthermore, the 10-Mb/s BPSK data communication link is evaluated at 80 GHz with a 20-dB signal-to-noise ratio at 1 m. The 160-GHz vector modulators offer additional modulations.

Ultrathin and Flexible Reflective Polarization Converter Based on Metasurfaces With Overlapped Arrays

In this letter, an ultrathin reflective polarization converter with the total thickness of 1/62 wavelengths is proposed to realize the high efficiency of cross-polarization conversion at 32 GHz. Two metasurfaces overlapped on the same layer with a displacement are designed to improve its polarization conversion performance, angular stability, and conformal adaptability. Due to the flexibility of the polyimide substrate, a planar and a conformal converter are conveniently fabricated by the printed circuit board technology. Experimental results show that the maximum conversion efficiency of the planar converter is higher than 94.3%, which is rather close to the simulation prediction. Meanwhile, a cross-polarization conversion efficiency of 88.1% can be obtained by the conformal converter with a 100 mm curvature radius, which demonstrates the validity of the overlapped array design. Due to the ultrathin thickness and flexibility, the proposed converter has great application potential in polarization control devices, on-chip antennas, and wearable antennas.

A Zero Bias J-Band Antenna-Coupled Detector in 65-nm CMOS

An improved topology for sub-THz radiation detection realized in 65 nm CMOS, including an on-chip antenna and using zero biasing is presented in this article. The topology is based on a differential Colpitts topology working in reverse-mode and leverages the nonlinearity with respect to <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">v_DS</i> in subthreshold operation to rectify. The use of tuned inductors at the gates and sources of the transistor core create degenerative resonance feedback, which further enhances the responsivity while working with zero bias eliminates 1/ <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">f</i> noise to improve the NEP. Measurements demonstrated a voltage responsivity as high as 2 kV/W with a 3 dB RF BW of at least 50 GHz centered at 315 GHz and a record NEP of down to 3.5 pW/√Hz, verified both at zero-IF and using chopping from 0.5 Hz up to 2 kHz. The chip occupies an area of 0.165 mm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> including pads.

A Multimodal Dielectric Waveguide-Based Monopulse Radar at 160 GHz

For highly integrated imaging systems above 100 GHz, the complexity and chip area increase significantly with an increasing number of channels. In addition, bulky dielectric lenses prevent applications in spatially restricted surroundings. The presented concept of an imaging monopulse radar with a mechanically flexible front end reduces the required chip area and allows the antenna to be placed in any desired position apart from the sensitive electronics. The radar system is based on a two-channel 160-GHz microwave monolithic integrated circuit (MMIC) feeding a flexible dielectric waveguide. Depending on the angle of the incidence signal, a sum mode (HE11 mode) and a difference mode (HE21 mode) are excited in the dielectric waveguide. MMIC and waveguide are connected by a self-aligning transition reducing the requirements for packaging accuracy. The required chip area of the transition is only $0.022\lambda ^{2}$ with a spacing between the on-chip antennas of $\lambda /4$ . The measured ambiguity-free region between −18° and 15° is defined by the modified elliptical lens antenna focusing in the $E$ -plane only. A mechanical bending of the flexible waveguide is possible down to a radius of at least 2 cm without affecting the angle estimation capability.

Miniaturized On-Chip NFC Antenna versus Screen-Printed Antenna for the Flexible Disposable Sensor Strips

With the ongoing trend toward miniaturization via system-on-chip (SoC), both radio-frequency (RF) SoCs and on-chip multi-sensory systems are gaining significance. This paper compares the inductance of a miniaturized on-chip near field communication (NFC) antenna versus the conventional screen-printed on-substrate ones that have been used for the transfer of sensory data from a chip to a cell phone reader. Furthermore, the transferred power efficiency in a coupled NFC system is calculated for various chip coil geometries and the results are compared. The proposed NFC antenna was fabricated via a lithography process for an application-specific integrated circuit (ASIC) chip. The chip had a small area of 2.4 × 2.4 mm2, therefore a miniaturized NFC antenna was designed, whereas the screen-printed on-substrate antennas had an area of 35 × 51 mm2. This paper investigates the effects of different parameters such as conductor thickness and materials, double layering, and employing ferrite layers with different thicknesses on the performance of the on-chip antennas using full-wave simulations. The presence of a ferrite layer to increase the inductance of the antenna and mitigate the interactions with backplates has proven useful. The best performance was obtained via double-layering of the coils, which was similar to on-substrate antennas, while a size reduction of 99.68% was gained. Consequently, the coupling factors and maximum achievable power transmission efficiency of the on-chip antenna and on-substrate antenna were studied and compared.

Study on on-Chip Antenna Design Based on Metamaterial-Inspired and Substrate-Integrated Waveguide Properties for Millimetre-Wave and THz Integrated-Circuit Applications

This paper presents the results of a study on improving the performance parameters such as the impedance bandwidth, radiation gain and efficiency, as well as suppressing substrate loss of an innovative antenna for on-chip implementation for millimetre-wave and terahertz integrated-circuits. This was achieved by using the metamaterial and the substrate-integrated waveguide (SIW) technologies. The on-chip antenna structure comprises five alternating layers of metallization and silicon. An array of circular radiation patches with metamaterial-inspired crossed-shaped slots are etched on the top metallization layer below which is a silicon layer whose bottom surface is metalized to create a ground plane. Implemented in the silicon layer below is a cavity above which is no ground plane. Underneath this silicon layer is where an open-ended microstrip feedline is located which is used to excite the antenna. The feed mechanism is based on the coupling of the electromagnetic energy from the bottom silicon layer to the top circular patches through the cavity. To suppress surface waves and reduce substrate loss, the SIW concept is applied at the top silicon layer by implementing the metallic via holes at the periphery of the structure that connect the top layer to the ground plane. The proposed on-chip antenna has an average measured radiation gain and efficiency of 6.9 dBi and 53%, respectively, over its operational frequency range from 0.285–0.325 THz. The proposed on-chip antenna has dimensions of 1.35 × 1 × 0.06 mm3. The antenna is shown to be viable for applications in millimetre-waves and terahertz integrated-circuits.

Multi-Feed Antenna and Electronics Co-Design: An E-Band Antenna-LNA Front End With On-Antenna Noise-Canceling and Gₘ-Boosting

This article presents an E-band low-noise amplifier (LNA) co-designed and co-integrated with an on-chip multifeed antenna for antenna-level LNA noise-canceling and gm -boosting. Different from conventional approaches that view antennas as a simple 50-Ω radiation load, we exploit antennas as multi-feed passive radiating networks with direct onantenna signal conditioning and processing capabilities. Such an antenna-electronics co-design concept can potentially advance wireless front-end performance beyond electronics-only designs and opens the door to a plethora of front-end innovations. We also propose equivalent circuits to model multi-feed antenna systems and elucidate on-antenna signal processing operations. As a proof of concept, we propose an antenna-LNA co-designed architecture and explore the interactions among a common-gate (CG) LNA path, a common-source (CS) LNA path, and a pair of near-field coupled folded slot antennas for on-antenna noise-cancellation and g <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</sub> -boosting. In the measurements, a true V-factor radiation method is introduced as a new approach to measure the noise figure (NF) of the on-chip multi-feed antenna and LNA/RX integration. Then, we perform the conventional sensitivity-based NF measurement. Both measurements show accurate and consistent NF characterization at high millimeter-wave (mm-Wave). The E-band antenna-LNA front end is implemented in the Globalfoundries 45-nm CMOS SOI process and demonstrates 4.8-dB NF with 2.2-dBm IIP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> , achieving the best reported FoM at similar frequencies. Furthermore, over-the-air modulation tests are demonstrated, supporting >10-Gb/s high-fidelity high-order QAM signals over an E-band wireless link.

A 28 GHz and 60 GHz Dual-Band On-Chip Antenna for 5G-Compatible IoT-Served Sensors in Standard CMOS Process

In this communication, a dual-band on-chip meander-line monopole antenna is proposed and demonstrated for emerging fifth-generation (5G)-compatible Internet of Things (IoT)-served sensor nodes. The targeted 28/60 GHz compact antenna is a hybrid structure of meander-line monopole antenna and packaging substrate to both shield the antenna from its deployed environment and to enhance the antenna radiation efficiency as well as the gain over the two bands of interest. The antenna model and design analysis are presented in this work together with a fabricated and tested 65 nm bulk CMOS chip. The prototyped on-chip antenna exhibits a measured gain of −10 dBi at 28 GHz with a bandwidth of 5.3% and 0 dBi at 60 GHz with a bandwidth of 5.9%. A radiation efficiency of 45% and 30% is obtained at 28 and 60 GHz, respectively. The antenna occupies a space of $0.25\times0.3$ mm2 ( $\lambda /43\times \lambda /35.7$ at 28 GHz). The on-chip antenna solution proposed in this work addresses the highly desirable yet challenging overall design of future wireless systems (5G and beyond) which hit the mark on compactness, cost, and compatibility. In addition, this work provides a viable design platform for achieving frequency diversity and multifunctionality of future wireless involving power harvesting, data transfer, and sensing operation.

Breaking FOV-Aperture Trade-Off With Multi-Mode Nano-Photonic Antennas

Nano-photonic antennas are one of the key components in integrated photonic transmitter and receiver systems. Conventionally, grating couplers, designed to couple into an optical fiber, suffering from limitations such as large footprint and small field-of-view (FOV) have been used as on-chip antennas. The challenge of the antenna design is more pronounced for the receiver systems, where both the collected power by the antenna and its FOV often need to be maximized. While some novel solutions have been demonstrated recently, identifying fundamental limits and trade-offs in nano-photonic antenna design is essential for devising compact antenna structures with improved performance. In this paper, the fundamental electromagnetic limits, as well as fabrication imposed constraints on improving antenna effective aperture and FOV are studied, and approximated performance upper limits are derived and quantified. By deviating from the conventional assumptions leading to these limits, high-performance multi-mode antenna structures with performance characteristics beyond the conventional perceived limits are demonstrated. Finally, the application of a pillar multi-mode antenna in a dense array is discussed, an antenna array with more than 95% collection efficiency and 170 $^\circ$ FOV is demonstrated, and a coherent receiving system utilizing such an aperture is presented.

Coherent Radiation From a Swarm of Wirelessly Powered and Synchronized Sensor Nodes

This paper presents a novel technique to synchronize a swarm of sensor nodes at the RF domain and produce coherent radiation from the sensor nodes to increase the amplitude of the reflected signal. A network is formed by an array of microchips that are wirelessly powered, and upon activation, radiate back an RF signal. The phase of the radiated signals from each microchip is synchronized using a wireless reference signal. This technique results in a coherent amplitude combing and power amplification. The microchips are fabricated in a 180-nm CMOS SOI technology. Each microchip occupies a total area of $3.9\times 0.7\,\,\textit {mm}^{2}$ that includes three on-chip dipole antennas that are used for power delivery, injection locking, and back RF reflection. Measurement results reveal that a reference signal in a frequency range of 7.72-7.79 GHz can successfully synchronize the reflected signals radiated from the microchips through a sub-harmonic injection locking scheme. A wireless reference signal of 7.733 GHz synchronizes an array of $2\times2$ microchips. The microchips are locked to half of the reference frequency and produce coherent radiation at 3.866 GHz. This scheme results in a power elevation of ~12 dB on the reader side.

Design of a SIW on-chip antenna using 0.18-μm CMOS process technology at 0.4 THz

A 0.4-THz on-chip antenna (OCA) is configured with high radiation efficiency and high gain, utilizing standard CMOS process technology. In this design, the back cavity is formed by connecting a top and bottom metal layer, which is connected through the vias, named substrate-integrated-waveguide (SIW). This back cavity finds to suppress the surface wave and separates the radiation towards the low-resistive substrate. The slotted radiator is constructed on the top metal layer that leads to enhance the radiation performance in broadside direction. The projected antenna size of 490 × 450 μm2 and shows a 3-dB gain bandwidth of ∼ 39 %, a directivity of ∼7.02 dBi, a radiation efficiency of ∼ 87.9 % in the frequency range from 0.380 THz to 0.420 THz. This OCA is suitable for various THz applications in suggested band.

Application of substrate as ground for designing 3D on-chip dielectric resonator antenna with improved characteristics

This paper presents a simple method to design 3D on-chip antenna with improved gain and efficiency. In the proposed method, without introducing any additional metal-based ground layer, a low resistive Si substrate is used as the ground plane for a monopole fed dielectric resonator antenna (DRA). A cylindrical DRA (CDRA) made-up of Barium Titanate (BaTiO3,εr = 24) is placed on the top side of the oxide coated Si wafer and is excited under TM011 mode with a coaxial probe inserted from the bottom of the substrate using TSV (through silicon via) hole. The proposed on-chip CDRA (OC-CDRA) designed within the foot-print area of λ0/6.12 ×λ0/6.12 provides the peak radiation gain and efficiency of 1.2 dBi and 87% respectively at its resonating frequency of 3.5 GHz. Also, it shows 14% fractional bandwidth (FBW) with respect to its resonating frequency. Further, the isolation between co- and cross (×) polarization components along the maximum radiation direction of the two principle planes with ϕ = 0° and 90° are obtained as 34 dB and 39 dB respectively. Preparing the dielectric material, the proposed OC-CDRA is fabricated and the experimentally measured results show good agreement with the simulated results.

A 64-Pixel 0.42-THz Source SoC With Spatial Modulation Diversity for Computational Imaging

This article presents a terahertz (THz) source system-on-a-chip (SoC) specifically designed for computational imaging with a single-pixel camera (SPC). The SoC consists of an 8 × 8 array of independent, frequency-unlocked THz sources that together radiate maximum 10.3-dBm power at 0.42 THz. Each source pixel is composed of a fundamental Colpitts oscillator, followed by a common-collector doubler and an on-chip circular slot antenna. The THz power radiated from the array can be modulated in space by turning the pixels on or off individually with 100% modulation depth. The SoC integrates a dedicated memory space where 64 of such spatial patterns can be stored and triggered externally at up to 10-MHz modulation rate. The spatial modulation can be additionally multiplexed with separate programmable chopping rates for individual pixels. The combined modulation diversity provides a highly reconfigurable THz light projection for SPCs. Furthermore, each pixel also incorporates a built-in power-test (BIST) for an in situ radiation power monitoring and calibration. All of the aforementioned functions are programmable with an integrated application-specific integrated circuit (ASIC) through a standard SPI interface. This integration level readily allows low-cost aperture scaling by combining multiple chips at the board level. The SoC was applied in a compact, 8 × 8 pixel, silicon-only THz SPC that captures transmission-mode images at 25 frames/s with 40-dB voltage dynamic range. With an appropriate receiver and baseband processing, the imaging speed of such SPCs can be extended to thousands of frames per second.

High-Gain On-Chip Antenna Design on Silicon Layer With Aperture Excitation for Terahertz Applications

This letter investigates the feasibility of designing a high gain on-chip antenna on silicon technology for subterahertz applications over a wide-frequency range. High gain is achieved by exciting the antenna using an aperture fed mechanism to couple electromagnetics energy from a metal slot line, which is sandwiched between the silicon and polycarbonate substrates, to a 15-element array comprising circular and rectangular radiation patches fabricated on the top surface of the polycarbonate layer. An open ended microstrip line, which is orthogonal to the metal slot-line, is implemented on the underside of the silicon substrate. When the open ended microstrip line is excited it couples the signal to the metal slot-line which is subsequently coupled and radiated by the patch array. Measured results show the proposed on-chip antenna exhibits a reflection coefficient of less than −10 dB across 0.290–0.316 THz with a highest gain and radiation efficiency of 11.71 dBi and 70.8%, respectively, occurred at 0.3 THz. The antenna has a narrow stopband between 0.292 and 0.294 THz. The physical size of the presented subterahertz on-chip antenna is 20 × 3.5 × 0.126 mm3.