I.D. Robertson

Capacitively-tuned split microstrip resonators for RFID barcodes

A new method of realising RF barcodes is presented using arrays of identical microstrip dipoles capacitively tuned to be resonant at different frequencies within the desired licensed-free ISM bands. When interrogated, the reader detects each dipoles resonance frequency and with n resonant dipoles, potentially 2/sup n/-1 items in the field can be tagged and identified. Results for RF barcode elements in the 5.8 GHz band are presented. It is shown that with accurate centre frequency prediction and by operating over multiple ISM and other license-exempt bands, a useful number of information bits can be realised. Further increase may be possible using ultra-wideband (UWB) technology. Low cost lithographic printing techniques based on using metal ink on low cost substrates could lead to an economical alternative to current RFID systems in many applications.

V-band single chip, direct carrier BPSK modulation transmitter with integrated patch antenna

A single chip V-Band pHEMT technology transmitter with wideband direct BPSK modulation and on-chip dual band patch antenna is reported. The transmitter features, 10% bandwidth electronic tuning range, substantial power output, injection locking capability, low power consumption and good patch antenna radiation characteristics. As such it is well suited to wireless digital communications systems as well in radar and phased array applications.A single chip V-band pHEMT technology transmitter with wideband direct BPSK modulation and on-chip dual band patch antenna is reported. The transmitter features, 10% bandwidth electronic tuning range, substantial power output, injection locking capability, low power consumption and good patch antenna radiation characteristics. As such it is well suited to wireless digital communications systems as well in radar and phased array applications.

Monolithic resistive mixers for 60 GHz direct conversion receivers

Single-ended and balanced monolithic mixers for direct conversion at V-band are presented. Resistive PHEMTs are employed with reactive feedback between gate and drain, and IF extraction from the source. Low conversion loss is achieved with high isolation and low intermodulation. Successful demodulation of a 1 Mbit/s BPSK signal at 60 GHz demonstrates the technique for millimeter wave direct conversion receivers.

A compact MMIC balun using spiral transformers

A MMIC balun has been realised using spiral transformers in a Marchand configuration. This arrangement results in a simple, compact design with good performance. Using standard foundry processing, amplitude balance of 0.2 dB and phase balance of 10/spl deg/ was achieved from 2 to 6 GHz.

A millimeter-wave monolithic sub-harmonically pumped resistive mixer

This paper describes a sub-harmonically pumped single chip resistive mixer consisting of two pHEMTs, a LO Marchand balun and RF/IF filters. The balun achieves 0.2 dB and 5/spl deg/ of amplitude and phase balance from 17 to 34 GHz. This provides the mixer with over 30 dB of LO rejection and a minimum conversion loss of 9.5 dB over a 34 to 40 GHz RF bandwidth with only 5 dBm of LO power.

A 60 GHz 256 QAM balanced vector modulator for short range LOS communication applications

An I-Q type vector modulator employing two orthogonal bi-phase amplitude reflection type modulators has been demonstrated which sets a new benchmark for a multilevel direct carrier modulator for digital communications. The 60 GHz modulator uses design techniques and technology capability to reduce hardware complexity in communication applications. The modelling and design of the balanced I-Q vector modulator are reported, followed by the measured performances.An I-Q type vector modulator employing two orthogonal bi-phase amplitude reflection type modulators has been demonstrated which sets a new benchmark for a multilevel direct carrier modulator for digital communications. The 60 GHz modulator uses design techniques and technology capability to reduce hardware complexity in communication applications. The modelling and design of the balanced I-Q vector modulator are reported, followed by the measured performances.

Miniature 38 GHz couplers and baluns using multilayer GaAs MMIC technology

In this paper, miniature hybrid couplers and baluns using 3D-MMIC technology are presented. These circuits include a branch-line coupler, a rat-race coupler and an all-ports matched planar Marchand balun, all designed at the center frequency of 38GHz. They are fabricated using a multilayer MMIC process employing five metal layers and four layers of BCB dielectric film on a GaAs substrate. With this, size reduction as much as 6 times over their standard counterparts has been achieved and they are thus suitable for the implementations of compact circuits such as balanced mixers and amplifiers.

Rectangular Waveguide Filters Using Photoimageable Thick-film Processing

Band-pass H-plane offset Rectangular Waveguide filters at W-Band (75-110GHz) and F-Band (90-140GHz) are presented. The filters are designed using multilayer thick-film processing with Alumina as a base. The process incorporates photoimageable thick-film paste for better precision and sharpness at the corners of the offsets. The filters do not require any tuning and are described with regard to their manufacture and measurement results. The centre frequencies are 85GHz and 105GHz and their relative bandwidths are ¿ 10%. The filters are de-embedded using a specially designed calibration set which uses the multiline TRL technique. Insertion loss of 5 dB and return loss less than 15 dB is measured for waveguide thickness of 18¿m.

Design and Performance of A Novel Balanced Self-Oscillating Mixer

A balanced self-oscillating mixer has been fabricated and tested. By utilising the symmetrical configuration technique, the circuit provides anti-phase output signals. Its inherent mixing is given by the non-linear mechanism of an active device. Therefore, anti-phase intermediate frequency performance has been investigated. In addition, the RF port is taken into account in order to obtain conversion gain. Unlike the typical mixer, the balanced self-oscillating mixer can achieve smaller size and consume less power.

Ruthroff transmission line transformers using multilayer technology

This paper presents Ruthroff type transmission line transformers for wideband impedance matching at microwave frequencies fabricated using both thin film microstrip (TFMS) operating up to approximately 30 GHz and multilayer MMIC processes operating up to approximately 60 GHz.