G. Zdasiuk

5-100 GHz InP CPW MMIC 7-section distributed amplifier

The development of a single-stage 5-100-GHz InP monolithic microwave IC (MMIC) amplifier with an average gain of more than 5.0 dB is reported. This MMIC distributed amplifier has the highest frequency and bandwidth of operation (5-100 GHz) reported for wideband amplifiers. The active devices in this seven-section distributed amplifier are 0.1- mu m mushroom-gate InGaAs-InAlAs lattice-matched HEMTs on a semiinsulating InP substrate. Coplanar waveguide is the transmission medium for this 100-GHz MMIC with an overall chip dimension of 500 by 860 mu m. This is the first 100-GHz coplanar waveguide circuit on an InP substrate.<<ETX>>

Coplanar Waveguides Used in 2-18 GHz Distributed Amplifier

This paper describes the use of coplanar waveguide as an alternative transmission medium in a monolithic distributed amplifier. The coplanar waveguide layout substantially reduces coupling effects between adjacent lines, and eliminates the need for via holes and substrate thinning, leading to higher fabrication yields. The resulting device reported here is a compact (1.3 x 1.5mm) low noise distributed amplifier on a thick GaAs substrate (15 mil), with a gain of 6.0 +- 0.5dB over the frequency range of 2 - 18GHz.

High-gain, low-noise monolithic HEMT distributed amplifiers up to 60 GHz

Ultrabroad-bandwidth distributed amplifiers with cutoff frequencies of 45 to 60 GHz were developed using 0.25- mu m high-electron-mobility transistors (HEMTs) with a mushroom gate profile. Both single and cascode HEMTs were used as the active devices in the amplifiers. A measured gain as high as 10+or-1 dB from 5 to 50 GHz and a gain of 8+or-1 dB from 5 to 60 GHz, respectively, were achieved from amplifiers using cascode HEMTs. The measured noise figure for these amplifiers is approximately 3-4 dB in the Ka-band. The chip size is 2.3*0.9 mm. Device considerations, circuit design, monolithic IC fabrication, and the measured performance of the amplifiers are outlined.<<ETX>>

A 2-20 GHz, High-Gain, Monolithic HEMT Distributed Amplifier

A low-noise 2-20 GHz monolithic distributed amplifier utilizing 0.3-micron gate-length HEMT devices has achieved 11-dB +- 0.5 dB of gain. This represents the highest gain reported for a distributed amplifier using single FET gain cells. A record low noise figure of 3 dB was achieved mid-band (7-12 GHz). The circuit design utilizes five HEMT transistors of varying width with gates fabricated by E-beam lithography.

A monolithic 40-GHz HEMT low-noise amplifier

A description is given of a monolithic, reactively matched 40-GHz low-noise amplifier using a 0.25- mu m high-electron-mobility transistor (HEMT) as the active device. Standard processing techniques were used for most of the fabrication steps. An amplifier using a triangular gate profile achieved approximately 6.5-dB gain and a 5-dB noise figure from 38 to 44 GHz. The gain of the amplifier increased to 8 dB and the noise figure decreased to 4 dB when the gate was replaced by one with a mushroom-like profile. The chip size is 1.1 mm*1.1 mm.<<ETX>>A monolithic, single-stage HEMT (high-electron-mobility transistor) low-noise amplifier has been developed at 40 GHz. This amplifier includes a single 0.25- mu m gate-length HEMT active device with on-chip matching and biasing circuits. A gain of 6.5 dB and a noise figure of 5 dB were measured from 38 to 44 GHz. By replacing the triangular gate profile with a mushroom gate profile the amplifier achieved 8-db gain and 4-dB noise figure from 36 to 42 GHz. The chip size is 1.1 mm*1.1 mm.<<ETX>>

A High Gain, Monolithic Distributed Amplifier Using Cascode Active Elements

A novel, monolithic, distributed amplifier has achieved a record gain of over 10 dB from 2-18 GHz. The design utilizes five quarter-micron gate length, cascode connected, FETs on epitaxial material . Circuit simulations predict over 10 dB gain from 2-30 GHz for an amplifier with seven active elements. Novel features of the design, fabrication and testing are discussed.

A monolithic Ka-band HEMT low-noise amplifier

A monolithic, single-stage high-electron-mobility transistor (HEMT) low-noise amplifier was developed for the 20-40-GHz band. This amplifier includes a single 0.25- mu m-gate-length HEMT active device with on-chip matching and biasing circuits. A gain of approximately 6 dB from 20 to 38 GHz and a noise figure of approximately 5 dB from 26.5 to 38 GHz were measured. The chip size is 2.2 mm*1.1 mm.<<ETX>>

Via hole studies on a monolithic 2-20 GHz distributed amplifier

The effect of source inductance on the performance of a distributed amplifier is investigated. A simple theoretical analysis shows that optimum performance is obtained with as low a source inductance as possible (as would be intuitively expected), and that the flattest gain and minimum gate line attenuation occur with the inductance common to the whole amplifier rather than parceled out to each FET individually, as would occur for a MIC distributed amplifier. A novel through-the-wafer via hole process has been developed for a low-inductance contact on monolithic circuits. A 2-20 GHz variable-gate-width monolithic distributed amplifier fabricated with this via-hole grounding technique has demonstrated a 2-dB gain improvement as well as a flatter gain profile compared to that without via grounding. Evidence is presented that indicates that MMIC (monolithic microwave integrated circuit) designs may not be as ideal as expected with regard to being typified by the common inductance case. >

Real-time multirate FIR digital filters in RF transient spectroscopy applications and their implementation on TMS320-C30

The application of multirate finite-impulse-response (FIR) filtering to radio-frequency (RF) transient spectroscopy is reported. The implementation issues of these multirate filters for sampling rate reduction (decimation) and sampling rate increase (interpolation) in this application are discussed. These implementation issues include the transient response of the digital filters and the aliasing noise due to the decimation process in the passband and the stopband of the digital decimating filters. All implementation measurements reported were performed on a TMS320-C30 DSP (digital signal processor) chip.<<ETX>>

Sensitivity of a 40 GHz HEMT low-noise amplifier to material and processing variations

The design of a monolithic, single-stage low-noise amplifier at 40 GHz for application to satellite communication is presented. The amplifier includes a single 0.25- mu m-gate-length HEMT active device with on-chip matching and biasing circuits. A gain of 8 dB and a noise figure of 4 dB were measured from 36 to 42 GHz for an amplifier with a mushroom gate profile. Using a triangular-gate-profile device with a lower gate-to-drain feedback capacitance, the amplifier achieves a 10 dB peak gain at 43 GHz. The chip size is 1.1*1.1 mm/sup 2/. >