A wideband CPW ring power combiner with low insertion loss and high port isolation

In this paper we present a coplanar waveguide (CPW)-based ring power combiner that exhibits less than 0.8 dB insertion loss, better than 15 dB port match and higher than 22 dB isolation loss over the frequency range from 50 GHz to 100 GHz. Compared with the conventional 2-way Wilkinson combiner, the proposed ring power combiner replaces the resistor between the two input ports with two quasi quarter-wave CPWs, a 180º CPW phase inverter, and two resistors that lead to frequency-insensitive port isolation and wideband port match. The power combiner is realized using an electron beam-based GaAs MMIC process along with simple electron beam airbridge technology. These results agree well with 3D full-wave simulations

Development of a low actuation voltage RF MEMS switch

This paper reports on the design of a novel ultra low actuation voltage, low loss radio frequency micro-electro-mechanical system (RF MEMS) capacitive shunt switch. The concept of the switch relies on a mechanically unconstrained armature actuated over a coplanar waveguide using electrostatic forces. The minimum actuation voltage of the switch is <2V, with an isolation of 40dB and insertion loss <0.7dB at 78GHz

Integrated Micromachined Millimeter Wave Patch Antenna

We have proposed 3-D micromachined elevated patch antenna for G-band (140GHz to 220GHz) applications. ne antenna is consisted of coplanar waveguide (CPW) feed line, a feeding post, air-bridge, supporting posts, and elevated patch. The antenna topology effectively creates a low dielectric substrate and undesired substrate effects can be eliminated, since the antenna substrate is essentially air which the lowest possible dielectric constant. This will increase the radiation efficiency, gain, and the radiation bandwidth. The measurement result shows the bandwidth is about 7GHz, from 170GHz to 177GHz with nearly constant broadside radiation pattern. Also, this work has demonstrated the capability of fabricating a high performance antenna design in a MMICs compatible proces

HF antenna prototype for geophysical ground penetrating radar

We describe an HF antenna design and implementation intended for ground penetrating radar applications in glaciology and hydrology. The HF antenna is based on modifications of a twin terminated folded dipole design. Prototypes of the HF antenna were built and then tested with a frequency-modulated continuous-wave radar operating from 25 MHz to 45 MHz, in a preliminary experiment for subsurface water detection

Understanding Pure Character-Based Neural Machine Translation: The Case of Translating Finnish into English

An ultra-low-power monolithic amplifier using 50-nm gate-length GaAs metamorphic high-electron-mobility transistor (MHEMT) has been designed and fabricated by a coplanar waveguide monolithic microwave integrated circuit process

Impact of waveguide aperture dimensions and misalignment on the calibrated performance of a network analyzer from 140 to 325GHz

We present experimental results from studying the impact of waveguide aperture dimensions and misalignment on the calibrated electrical performance of a vector network analyzer from 140 to 325GHz. It is shown that the calibrated transmission response is not adversely affected by waveguide irregularities or aperture misalignment. In contrast, we observed that the calibrated reflection response is much more sensitive to these mechanical imperfections. Our initial results suggest that waveguide misalignment may have a greater impact on the calibration accuracy of network analyzers operating beyond 140GHz

Coplanar ring divider with wideband high isolation performance

In this letter, the design and measurement of a new ring power divider exhibiting wideband high isolation is presented. Coplanar techniques are used to achieve a compact and truly uniplanar design. The design is demonstrated by a prototype, operating at K-band, that has been monolithically fabricated using a GaAs MMIC process with airbridge technology. The measured insertion loss is 0.6 dB at the center design frequency of 25 GHz. The output port isolation is better than 20 dB across a wide bandwidth from 10 MHz to 50 GHz. The output amplitude and phase balance is within ±0.5 dB and ±2°, respectively, in the bandwidth from 10 MHz to 43 GHz

A wide bandpass filter with defected ground structure for wide out-of-band suppression

This paper presents a wide bandpass filter (BPF) with low insertion loss and excellent harmonic out-of-band suppression over a very wideband. The filter consists of a standard ultra-wideband bandpass filters design approach combined with periodic defected ground structure (DGS), which is able to inhibit signal propagation over a wideband. To realize this filter, a wideband microstrip BPF with a bandwidth covering 3.7 GHz is implemented in an RO4350 substrate (epsilon(r) = 3.66, h = 0.762 mm). This bandpass filter shows a wide bandwidth with measured insertion loss better than 0.9dB and spurious suppression better than 24 dB

A broadband circular combiner/divider for planar Gunn oscillators

In this paper, a circular power combiner/divider using coplanar strip-lines operating at the centre frequency of 30 GHz is demonstrated. The combiner/divider has a coplanar strip-line (CPS) crossover phase inverter and it shows good isolation (< −22 dB) up to 55 GHz. The combiner/divider is suitable for combining planar Gunn oscillators that operate in a wide frequency range

Parallel coupled-line bandpass filter with branch-line shape for G-band frequency

A parallel coupled-line planar bandpass filter (BPF) with branch-line shape using coplanar waveguide technology on GaAs substrate is presented. The unit parallel coupled-line BPF utilises a parallel coupledline resonator with an open-ended stub which has suppression response of spurious band. Four unit parallel coupled-line BPFs are integrated with branch-line shape and open-circuit stubs on input and output ports are also integrated for improvement of rejection performance. The proposed fourth-order filter was fabricated on GaAs substrate with dielectric thickness of 50 mm and gold thickness of 1.2 mu m. The fabricated fourth-order BPF shows a 3 dB bandwidth from 177 to 209 GHz frequency range with insertion loss of 6.5 dB, rejection of 38 dB and return loss better than 12 dB. It has a high resolution fractional bandwidth of 17%