8,184 research outputs found
Phenomenological Implications of the Topflavor Model
We explore phenomenologies of the topflavour model for the LEP experiment at
scale and the atomic parity violation (APV) experiment in the
atoms at low energies. Implications of the model on the peak data are
studied in terms of the precision variables 's. We find that the
LEP data give more stringent constraints on the model parameters than the APV
data.Comment: 23 pages (including 5 .eps figs), ReVTeX, the 1st revised version, to
appear in Phys. Lett.
High-Gain Amplifier Module Integrating a Waveguide into the Module Case for Millimeter Wave Applications
A high-gain amplifier module with integrated waveguide (WG) has been presented for millimeter wave applications. In order to improve the isolation between the amplification stages in the multi-stage amplifier module, an isolated WG is integrated into the module case. It is possible to effectively suppress the oscillation occurring in the high gain stage. Microstrip line (MSL)-to-WG transitions are designed and fabricated on a 5 mil thick RT5880 substrate for interconnection of the isolated WG, input/output WG and amplifier PCB in a cascaded two-stage high gain amplifier module. The transition loss of −0.44 dB is obtained at 40 GHz and return-loss (S11) bandwidth below −10 dB is from 34.1 to 50 GHz. The fabricated high-gain amplifier module shows a high gain over 39.7 dB from 38 to 41 GHz. At 38.7 GHz, its maximum gain of 44.25 dB is achieved
LTCC-Based System-in-Package (SiP) Technology for Microwave System Integration
Monolithic low-temperature co-fired ceramic (LTCC) SiP modules have been presented for microwave applications. In order to integrate almost passive circuits of a radio system into the LTCC substrate, key technologies such as suppressing parasitic resonant modes, low-loss transitions and compact passive devices have been investigated. Well analyzed mechanisms on the parasitic resonant modes and their suppressing methods have been applied to high-isolation SiP structures. A strip line (SL) to CPW vertical transition using a stepped via structure embedding air cavities has been devised and has been used to design a SL BPF. A surface mount technology (SMT) pad transition has been developed by utilizing a modified coaxial line. A LPF composed of vertical plate capacitors and helical inductors and a 2 × 2 array antenna have been developed. A 61 GHz heterodyne transmitter LTCC SiP module has been implemented by monolithically embedding all passive circuits such as a SL BPF, 2 × 2 array antenna, SMT pads and feeding lines into it. A 60 GHz amplitude shift-keying (ASK) transceiver LTCC SiP module has been implemented as small as 17.8 × 17.9 × 0.6 mm3 by integrating a high-isolation via fence and a LPF. They have been characterized in terms of an output power, spectrum and link test
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