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DC blocks are used frequently in planar circuits to enable separate dc voltage/current biasing of active components inserted along the transmission lines. In this letter, we present a slotline dc block design where the conductors of the transmission line can be physically broken while allowing the propagation of the RF signal across the discontinuity with negligible insertion loss. The dc block comprises two breaklines with narrow gaps, patterned on the two ground planes of a slotline with each breakline connected to an RF choke. The RF chokes present open circuit nodes that prevent the RF power from leaking into the breaklines gaps. We have fabricated and tested the dc block and demonstrated that the measured performance agrees very well with simulated results. The insertion loss was close to −0.5 dB in the designated range of 12–16 GHz, demonstrating that the RF leakage through the dc block is indeed negligible. [ABSTRACT FROM AUTHOR]

In this letter, we present a new $E$ -plane rectangular waveguide bend that can be micromachined using split-block fabrication. The 90° bend is created by machining two linear channels with a notch left in the outside corner. This notch significantly improves the return loss and the insertion loss of the bend. The primary advantage of this technique is that it produces a compact waveguide bend, minimizing both the size and the conduction loss of the waveguide circuit. Another advantage is that this technique only requires linear channels to be machined, thus it can be fabricated without requiring a computer numerically controlled (CNC) milling machine. The performance of this waveguide bend was optimized using electromagnetic simulation software, and the optimal reflection coefficient was found to be below −28 dB across the entire operational bandwidth of the waveguide. The simulated design was then validated using two experimental prototypes that were tested at microwave (12–18 GHz) and millimeter frequencies (140–220 GHz). [ABSTRACT FROM AUTHOR]

We present a broadband endfire planar circuit antenna that is suitable for applications in microwave, millimeter (mm), and submillimeter (sub-mm) wavelengths. We have cascaded two dipoles of different lengths in series to broaden the bandwidth. Two printed directors and a truncated ground plane are used to achieve high front-to-back (F/B) gain ratio. The parallel stripline feeding the antenna's drivers is connected directly to microstrip without an intermediate stage. This simple antenna design is easily integrated into microstrip circuits. In this letter, we focus on the design of a Ku-band antenna with 7 GHz bandwidth and F/B gain ratio of ~ 18 dB. Design and analysis of the antenna were performed using rigorous electromagnetic simulations, and we experimentally validated the performance of the antenna by measuring the beam patterns and return loss of an antenna fabricated on a Roger RO 4350 printed circuit board. Finally, we present two unique example applications of the antenna in the sub-mm detectors area. [ABSTRACT FROM PUBLISHER]

Presents the design of a novel two-element horn-reflector antenna, which has been used on an interferometer built for studying the anistropy in the cosmic microwave background (CMB). Components of the CMB; Description of the design and fields of the antenna; Calculation of the antenna fields and radiation pattern; Design parameters for the antenna.

Presents a study which described a procedure for stimulating the behavior of partially coherent submillimeter-wave antenna systems. Statistical vector fields; Matrix representation of partially coherent systems; Analysis of a circular-waveguide bolometer.

Describes the design and operation of a finline superconductor-insulator-superconductor mixer. Use of a horn-reflector antenna to feed the mixer; Fabrication of the superconducting circuit using planar-circuit technology and fully integrated tuning.