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Silicon tracking detectors operated at high luminosity collider experiments pose a challenge for current and future readout systems regarding bandwidth, radiation, space and power constraints. With the latest developments in wireless communications, wireless readout systems might be an attractive alternative to commonly used wired optical and copper based readout architectures. The WADAPT group (Wireless Allowing Data and Power Transmission) has been formed to study the feasibility of wireless data transmission for future tracking detectors. These proceedings cover current developments focused on communication in the 60 GHz band. This frequency band offers a high bandwidth, a small form factor and an already mature technology. Motivation for wireless data transmission for high energy physics application and the developments towards a demonstrator prototype are summarized. Feasibility studies concerning the construction and operation of a wireless transceiver system have been performed. Data transmission tests with a transceiver prototype operating at even higher frequencies in the 240 GHz band are described. Data transmission at rates up to 10 Gb/s have been obtained successfully using binary phase shift keying.

This paper presents a numerical and experimental study of a nearly confocal resonator with spherical mirrors at 12 GHz. The geometry was chosen in order to have a large quality factor for the diffraction losses, and thereby a weak coupling to external parasitic TE and TM modes, that propagate in a pipe on which the resonator may be installed. In turn, this allows a significant improvement of its signal-to-noise ratio, e.g., when used as a beam monitor. Index Terms--Beam diagnostics, confocal resonator, reflection and transmission coefficients.

The design of electrically steerable traveling wave microstrip antenna arrays is presented. Varactor diode based phase shifters implemented on the same metallic layer as the patch elements are used to provide a variable progressive phase shift in the array. Two antennas for the 5.8 GHz ISM band, manufactured as single layer printed designs on a standard PTFE soft substrate, are demonstrated. A ten-element beam-tilting vertical array using transmission type phase shifters is realized, yielding between 11.8 to 13.9 dBi gain for the 0[degrees] to 11[degrees] beam tilt tuning range. Using wide phase tuning range reflection type phase shifters a five-element horizontally scanning array with -32[degrees] to 32[degrees] steering range and 10.9-11.3 dBi gain has been realized. Index Terms--Microstrip antennas, microwave phase shifters, phased arrays, traveling wave antennas.

The integration of an on-chip folded dipole antenna with a monolithic 24-GHz receiver manufactured in a 0.8-[micro]m SiGe HBT process is presented. A high-resistivity silicon substrate (1000 [ohm] cm) is used for the implemented circuit to improve the efficiency of the integrated antenna. Crosstalk between the antenna and spiral inductors is analyzed and isolation techniques are described. The receiver, including the receive and an optional transmit antenna, requires a chip area of 4.5 [mm.sup.2] and provides 30-dB conversion gain at 24 GHz with a power consumption of 960 mW. Index Terms--Dipole antennas, heterojunction bipolar transistors (HBTs), monolithic microwave integrated circuit (MMIC) receivers.

The integration of K-band (20-40 GHz) full wavelength square wire- and slot-loop antennas on low resistivity (11-70 [OMEGA]cm) silicon substrates is addressed. By the use of polymer or silicon oxide/nitride membranes to support the slot or wire loop over micromachined trenches the efficiency of the antennas is enhanced while the majority of the bulk silicon within the apterture of the antenna is preserved to enable the integration of active devices. A 3.6 x 3.6 [mm.sup.2] large slot loop antenna chip with 200 [micro]m micromachined trench width yields 1.5 dBi gain at 29.5 GHz, while 1.0 dBi gain,is obtained at 24 GHz for a wire loop antenna on a 4.5 x 4.5 [mm.sup.2] large chip with 360 [micro]m wide trenches. Index Terms--Loop antennas, micromachining, silicon, slot antennas.

A computationally efficient global optimization method, the differential evolution algorithm (DEA), is proposed for the synthesis of uniform amplitude arrays of two classes, i.e., unequally spaced arrays with equal phases and unequal phases. Phase-only synthesis and the synthesis of uniformly exited unequally spaced arrays (position only synthesis) are compared and it is seen that, by using the unequal spacing, the number of array elements can be significantly reduced for attaining reduced sidelobe levels. From the DEA-based synthesis of unequally spaced arrays with uniform amplitudes and unequal phases, it is found that a tradeoff exists between the size of the unequally spaced arrays and the range of phases for the same radiation characteristics. The proposed synthesis technique using uniform amplitudes, unequal spacing, and unequal phases (position-phase synthesis) not only decreases the size of the array for the same sidelobe level compared to both the phase-only synthesis and position-only synthesis but also retains their advantages. Index Terms--Antenna arrays, pattern synthesis.

A compact design of an amplifying active reflect-antenna using a novel microstrip-T coupled-patch antenna is proposed. The dual-polarized ports of the microstrip-T coupled-patch antenna provide excellent RF isolation as well as dc isolation. The dc isolation helps in avoiding additional coupling capacitors in the RF path, thereby achieving reduced layout size and cross-polarization levels for the active reflect-antenna. The gain and monostatic radar cross section (RCS) measurement of the active reflect-antenna has been carried out using a time-domain technique based on a single dual-polarized antenna and vector network analyzer. The measured monostatic RCS and gains are then compared with the calculated ones using two different modeling approaches. Index Terms--Active reflect-antenna.

The effects of using a multicarrier amplifier (MCPA) in the transmit chain of a cellular frequency-division multiple-access system utilizing switched multibeam base-station antennas is investigated. By combining several carriers prior to amplification, the signal envelope will be time varying and the MCPA will introduce nonlinear distortion of the amplified waveforms. It is shown how the main beam direction and frequency of any intermodulation product of any order can be calculated. A frequency allocation scheme is presented that reduces the intermodulation distortion at the mobile users. By Monte Carlo simulations, the probability distribution function of the received intermodulation distortion power is estimated, assuming a GSM system, as a function of the number of antenna elements and the number of active users. Comparisons with a one-element reference antenna are made, and it is shown that the received intermodulation distortion power for the users in the system is substantially reduced when the number of beams is increased or the user activity is reduced. Index Terms--Amplifier distortion, antenna arrays, difital communication, frequency division multi-access, intermodulation distortion.

SiGe HBT was studied for temperature dependence and electrical properties.

Current noise in silicon germanium heterojunction bipolar transistors were analyzed at different biasing conditions using transimpedance amplifiers. The simultaneous measurement of both the base-lead noise and the collector-lead noise had enabled a calculation of the coherence between the signals. It was established that the dominant noise source is situated in the base emitter junction at the emitter side and not in the contact resistances. The use of the coherence function had been significant for the discrimination of the dominant noise source.

In this paper, the design of an active millimeterwave frequency doubler using an Si/SiGe heterojunction bipolar transistor (HBT) as the active device is studied. Simulations are made using a developed physics-based large-signal model for Si/SiGe HBT's, which includes thermal dependence. Despite the high-output operating frequency of the fabricated doubler being close to [f.sub.max] 67 GHz for the Si/SiGe HBT, the conversion efficiency in a not completely optimized circuit is found to be better than -12 dB. The 3-dB bandwidth for the doubler is approximately 7.4%. These results are found to be comparable to a heterojunction field-effect transistor (HFET) doubler operating equally close to its [f.sub.max].Simulated results of the doubler performance with varied terminating impedances for the HBT are presented as design aids.

Theoretical work on Single Barrier Varactor (SBV) diodes indicates that the efficiency of a tripler with a SBV diode has a maximum for a considerably smaller capacitance variation than previously thought. SBV diodes based on GaAs, InGaAs and InAs have been fabricated, and their dc properties have been tested. Detailed modelling of the carrier transport properties of the SBV device is carried out in two steps. First, the semiconductor transport equations are solved simultaneously using a finite difference scheme in one dimension. Secondly, the calculated IV-, and CV characteristics are used by a multiplier simulator to calculate the optimum impedances, and output powers at the frequencies of interest. We have developed an analysis technique which complements the harmonic balance technique. Finally, simulations for a case study of a 750 GHz multiplier show that InAs diodes perform favorably compared to GaAs diodes.

Ongoing research in the design of a 750 GHz Schottky varactor diode for frequency tripling is presented. The tripler, which was developed for use in solid state sources which act as local oscillators, exhibits an output energy of 120 microWatt and an efficiency of 0.8% at a 803 GHz frequency. Its design made use of the theory put forward by N.R. Erickson for submillimeter wave multipliers.

To achieve a large terahertz (THz) amplitude from a spintronic THz emitter (STE), materials with 100% spin polarisation such as Co‐based Heusler compounds as ferromagnetic layer are required. However, these compounds are known to loose their half‐metallicity in the ultrathin film regime, as it is difficult to achieve L21 ordering, which has become a bottleneck for the film growth. Here, the successful deposition using room temperature DC sputtering of the L21 and B2 ordered phases of the Co2FeAl full Heusler compound is reported. Co2FeAl is used as ferromagnetic layer together with highly orientated Pt as nonferromagnetic layer in the Co2FeAl/Pt STE, where an MgO (10 nm) seed layer plays an important role to achieve the L21 and B2 ordering of Co2FeAl. The THz generation in the Co2FeAl/Pt STE is presented, which has a bandwidth of 0.2–4 THz. The THz electric field amplitude is optimized with respect to thickness, orientation, and growth parameters using a thickness dependent model considering the optically induced spin current, superdiffusive spin current, inverse spin Hall effect, and the THz attenuation in the layers. This study, based on the full Heusler Co2FeAl compound opens up a plethora of possibilities in STE research involving full Heusler compounds. [ABSTRACT FROM AUTHOR]