Lens‐coupled folded‐dipole antennas for terahertz detection and imaging

Abstract

The authors report the design, simulation and characterisation of lens-coupled folded-dipole antennas (LC-FDAs) for terahertz (THz) detection and focal-plane imaging arrays. LC-FDAs operating at 200 GHz have been designed on semiinsulating silicon wafers with a resistivity larger than 20 000 Ω·cm. Even-odd mode analysis (EOA) has been performed to extract the currents of the two modes. The embedding impedance of the designed LC-FDAs has been simulated using conventional numerical electromagnetics, and the results show that a wide range of impedance values (both real and imaginary parts) can be achieved by changing the antenna geometry. This property makes LC-FDAs suitable for highperformance THz detectors in which impedance matching between antennas and devices is desired. From the currents calculated using EOA, the LC-FDA far-field radiation patterns, antenna directivity and Gaussian coupling efficiency for different lens structures have been examined using ray-tracing techniques. Good agreement between calculation results and measurement has been observed demonstrating the effectiveness of the above analysis approach. The single element FDA design has also been explored for use in high-resolution two-dimensional THz focal plane arrays by optimising the lens structure and evaluating the off-axis radiation patterns.

Responsivity and NEP Improvement of Terahertz Microbolometer by High-Impedance Antenna

“…A careful interlayer fabrication is then needed for a good insulation between the thermistor and heater. A higher impedance antenna could also be used to further improvement in THz responsivity by increasing the number of arms in the folded dipole antenna [ 59 ].…”

Minimum Lens Size Supporting the Leaky-Wave Nature of Slit Dipole Antenna at Terahertz Frequency

“…In the past, lens-coupled antennas, including dipole antennas [6,7], bow-tie antennas [8], annular-slot antennas [9], log-periodic antennas [10], and folded-dipole antennas [11], have been studied. In particular, many researchers focused on the coupling of leaky-wave antennas with lenses due to their important and attractive properties, for instance, their broad impedance bandwidth, high directivity, and simple feeding network [12].…”

Diseño de lentes metálicas usando la teoría de modos característicos.

“…El objetivo en los dos casos es conseguir un frente de onda plano [19]. Las lentes fueron ampliamente investigadas durante el desarrollo temprano de antenas de microondas [20] y en el procesamiento de imágenes [21][22][23][24][25][26].…”