A monolithic 250 GHz Schottky-diode receiver

Abstract

A 250 GHz monolithic Schottky-diode receiver based on a double-slot antenna is presented. The double-slot antenna is placed on an extended hemispherical high-resistivity silicon substrate lens. The measured DSB conversion loss and noise temperature at 258 GHz are 7.8 & 0.3 dB and 1600 f l00K for the antenna-mixer, respectively. A nonoptimal polyethylene Xd/4 matching-cap layer for the silicon lens improves the conversion loss and noise temperature by 1 dB, and another 0.7 dB improvement could be obtained with the use of a more optimal matching cap layer. The uniplanar double-slot antenna receiver is less than 0.3 x 1 mm in size including the IF filter and represents the first fully monolithic 250 GHz receiver to date. The measured performance is within 2-3 dB of the best 200' GHz waveguide receivers using planar Schottky diodes.' I. INTRODUCTLON"GRATED-CIRCUIT receivers consisting of a planar I antenna integrated with a matching network and a planarSchottky-diode or a three-terminal device offer many advantages over waveguide-based receivers at millimeter-wave frequencies. They are smaller, lighter, and less expensive to build than waveguide systems and can be easily produced in. large numbers for millimeter-wave applications. A potential candidate for excellent millimeter-wave performance is the double-slot antenna [2]- [4]. In this work, a planar Schottky diode and a CPW-line matching network are integrated with a double-slot antenna on GaAs to form a fully monolithic Schottky-diode receiver. The monolithic integration should result in minimum parasitic capacitance and series resistance. After fabrication, the double-slot receiver is placed on an extended hemispherical high-resistivity silicon substrate lens to result in high-gain patterns with high Gaussian coupling efficiency [5]. This design requires no via holes or a backing ground-plane. The GaAs substrate is therefore not thinned down to 100 pm (or less) thereby increasing the yield of the fabrication process. The application areas for this receiver are in millimeter-wave imaging arrays for remote-sensing and radio-astronomical systems. I 190 p Polveth Monolithic Double-slot Receiver 630 CaAs pm-thick wafer 570p"hick high-p Si wafer Ma<chi$ Cap (b) Fig. 1. The 250 GHz monolithic double-slot antenna receiver. (a) Top view. (b) Side view illustrating the high resistivity silicon lens, polyethylene matching cap, and GaAs wafer. DESIGNThe monolithic double-slot antenna receiver is shown in Fig. 1. The design of the double-slot receiver is a compromise between an antenna geometry that will result in a highefficiency Gaussian beam pattern, an input impedance from the antenndCPW-matching network that will result in high RF coupling to the planar diode, and a physical circuit that is relatively insensitive to fabrication variations. In the doubleslot antenna design, the length of the slots controls the H-plane pattem and the separation between the slot antennas controls the E-plane pattem. The slot antennas are chosen to be 0.3OXo-long (354 pm) with a separation ...

Effect of internal reflections on the radiation properties and input admittance of integrated lens antennas

“…Also, and need to be replaced by and , respectively. If the matching layer is included in the integrated lens antenna design, the same theoretical model can be applied, but then the Fresnel reflection coefficients have to be replaced by the "infinite" reflection coefficients from (3). The effect of the matching layer will be that the magnitude of the reflected magnetic field decreases and also an extra phase is introduced for each ray preventing the existence of a caustic near the slots.…”

“…One of the advantages of such a lens is that the beamwidth of the planar radiator is reduced, which makes it easier to use these antennas (with lens) in practical systems. A number of people have already successfully used the dielectriclens concept for millimeter-and submillimeter-wave receivers [1]- [3].…”

A Multichannel THz Detector Using Integrated Bow-Tie Antennas

“…Detectors by using integrated antennas to provide multichannel can significantly simplify the imaging system and save time. A three-element linear array of doubleslot antennas was fabricated and measured on a silicon lens at 258 GHz [13]. More recently, a 2 * 2 array of 280 GHz Schottky-barrier diode detectors using an on-chip patch antenna is fabricated in a 130 nm logic CMOS process and integrated into a 2D focal-plane image scanner [14].…”

Direct response of twin-slot antenna-coupled hot-electron bolometer mixers designed for 2.5 THz radiation detection

“…Such a coupling structure has been applied for a Schottky mixer at 250 GHz. 4 A twin-slot antenna combined with a microstripline has been used for a superconductorinsulator-superconductor mixer around 1 THz. 5,6 A twin-slot antenna/CPW combination has recently been introduced for HEBMs and evaluated experimentally.…”

“…A similar approach is used for a Schottky mixer by Gearhart and Rebeiz. 4 The intrinsic frequency-dependent coupling between the embedding impedance Z embed ϭZ 1 ϩZ 2 seen at the bridge terminals and the bolometer impedance Z HEB can now be calculated using…”