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SAW IF filters in Mobile Communications Networks Sunder Gopani Sawtek Inc. Orlando, FL As mobile communications networks are making headway in their global expansion, two digital systems are emerging as standards: the Global System for Mobile communications (GSM) and code-division multiple access (CDMA). GSM is implemented predominantly in Europe...

Coupling Behavior between Transmission Lines with Meshed Ground Planes in LTCC-MCMs Multilayer ceramic modules for high speed digital applications use meshed planes between the signal layers for shielding and power supply. Both wave impedances of the signal lines and coupling behavior between different signal layers are influenced by the...

A 1.9 GHz Adaptive Feedforward Power Amplifier A relatively low power feedforward amplifier for 1.9 GHz has been developed to demonstrate the feasibility of the adaptive feedforward linearization technique. The saturated two-tone output power of this amplifier is approximately 4 W. The measured third-order intermodulation is -18 dBc before...

Accurate and Efficient Modeling of Meander-line Polarizers A meander-line polarizer is a passive broadband device used to convert the polarization properties of a wave. When designed properly, the polarizer permits a linear polarized antenna to propagate circular polarization without any significant variations in the pattern performance. Modeling of the...

A Microwave Analog Frequency Divider Matjaz Vidmar Nova Gorica, Slovenia Many analog frequency divider circuits were invented during the age of the vacuum tube. Some of these circuits even survived the germanium transistor age, but most were forgotten following the availability of inexpensive monolithic digital ICs such as flip-flops...

Useful Filtering Techniques to Save Scarce Spectrum in Communications Systems Helen Wright Hewlett-Packard Co., Microwave Instruments Division Santa Rosa, CA Most communications systems fall into one of three categories: those that are bandwidth efficient, power efficient or cost efficient. Bandwidth efficiency describes the ability of a modulation scheme to...

Around the Circuit INDUSTRY NEWS Plainview, NY-based Aeroflex Inc. has acquired 90 percent of the common stock of France-based Europtest S.A. for approximately $1.1 M. Aeroflex will purchase the remaining 10 percent of the company over a three-year period at prices to be determined based upon net sales of...

COMPONENTS GaAs MMIC SPST Switches The model AS123-12 GaAs MMIC SPST switch features high isolation of 45 dB at 0.9 GHz and 52 dB at 1.9 GHz as well as low insertion loss. The unit offers single positive control voltage and +5 V operation. When used with the company's...

ANTENNAS Cellular/GSM/ISM Dual Linear Antennas These cellular/GSM/ISM dual linear antennas feature a low profile design for minimum visual impact, making them suitable for discreet antenna installations. The units provide for simultaneous reception and transmission of both vertically and horizontally linearly polarized signals in the 824 to 896 GHz, 880...

AMPLIFIERS Solid-state Microwave Amplifier The model 100S1G4 solid-state microwave amplifier provides 100 W minimum power in the 0.8 to 4.2 GHz range, which is used often in PCS, broadcast communications and other handheld wireless test applications. Local and remote control of the unit is available through its digital control...