The wireless sensor network system requires two antennas that have an output 90 phase difference as a comparison and use a very expensive material for high frequency. 5.5 GHz microstrip antenna frequency equipped with two output 90 degree phase difference in one antenna has been proposed. This is a new technique in telecommunication systems to produce directional antenna use more precise and efficient phase comparators by using cheap and easy to find material at 5.5 GHz frequency. This system package consists of a circular patch, a reflector, a double transmission line with a via hole that has the same frequency in one antenna and quadrature 90 degree hybrid coupler integrated each other. This antenna produces a phase angle difference 87.752 degrees (5 degrees of standard tolerance) and gains 5.82 dBi at 5.5GHz frequency. Overall size of the proposed antenna design is 90 mm times 35 mm with Phenolic White Paper - FR4 with a dielectric constant is 4.4.

5.5 Ghz Directional Antenna with 90 Degree Phase Difference Output

This brief presents a dual-band tunable concurrent passive phase shifter monolithic microwave integrated circuit utilizing a two-stage dual-branch phase tuning network topology. The designed phase shifter with two independent phase tuning bands operates at 5.9 GHz and 16 GHz. The dual-band phase shifter is fabricated in a $0.25~\mu \text{m}$ GaAs process and occupies a small chip area of 0.98 mm2 (including pads). Measurement results show that transmission phases in the two frequency bands can be tuned concurrently. Phase tuning range is greater than 105° in either band. Insertion losses of less than 2.8 dB and 3.5 dB are exhibited in 5.8~6 GHz and 15.8~16.2 GHz, respectively. And amplitude imbalances within the whole phase tuning range in 5.8~6 GHz and 15.8~16.2 GHz are less than 1.1 dB and 1.3 dB, respectively. The return losses are greater than 10 dB in both frequency bands. The phase shifter is employed in a four-element dual-band phased array network. The phased array is able to independently tilt its main beam toward −20° ~ +20° in either band.

A Tunable Concurrent Dual-Band Phase Shifter MMIC for Beam Steering Applications

This brief presents a compact-size tunable gain-equalizer for X-band phased-array RADAR applications in a 0.25- $ \mu \text{m}$ SiGe BiCMOS technology. An isolated nMOS-based variable resistance was used for the first time to tune the slope of the gain-equalizer. For nMOS, an isolated body created by a deep n-well was utilized to reduce insertion loss due to the substrate conductivity. Furthermore, the power-handling capability of the tunable gain-equalizer was improved thanks to the resistive body-floating technique. The designed tunable gain-equalizer operates in the frequency range from 8 to 12.5 GHz with a measured positive slope of 1 dB/GHz and 1 dB tunable slope. The effective chip area excluding the pads is 0.21 mm2, and the total area including pads is 0.31 mm2. To authors best knowledge, this brief is the first tunable gain-equalizer in SiGe technology presented for X-band phased-array RADAR applications.

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A Tunable SiGe BiCMOS Gain-Equalizer For X-Band Phased-Array RADAR Applications

An L-band SiGe HBT active differential equalizer with tunable positive/negative gain slopes has been realized. the active equalizer employs transistor-loaded parallel RC circuits in the load and feedback paths of the differential amplifier in order to achieve tunable positive/negative gain slopes simultaneously. The implemented active equalizer has achieved positive gain slopes up to + 13.2dB/GHz and negative gain slopes down to − 6.7dB/GHz across 0.1 to 0.8GHz. The active differential equalizer provides positive and negative gain slopes coincidently by making a gain variation larger at lower frequencies and smaller at higher frequencies to compensate for various types of the frequency-and temperature-dependent gain slopes.

An L-Band SiGe HBT Active Differential Equalizer with Tunable Positive/Negative Gain Slopes Using Transistor-Loaded RC-Circuits

In this paper, a broadband slope equalizer is proposed, which is mainly composed of a microstrip through line and a few branching structures. The physical mechanism of the sloped equalizer is analyzed in detail. The measured and simulated results demonstrate that the broadband equalizer has a gain control of −12 dB to −1 dB in the frequency band of 6 - 18 GHz. The branching structures reduce the total area of the equalizer while keeping the return loss less than −15 dB.

Design of 6-18GHz slope equalizer based on branching structures

L-band SiGe HBT active differential equalizers with variable inclination and position of the positive or negative gain slopes have been designed and fabricated for frequency and temperature compensation of microwave and optical systems. The active equalizer employs dual-resonant RLC circuits in the series feedback path of the differential amplifier for positive gain slopes or in the load for negative gain slopes. The implemented active equalizers have achieved positive gain slopes of +54 to +87dB/GHz across 0.2 to 0.6GHz as well as negative gain slopes of −55 to −95dB/GHz over 1.1 to 1.5GHz. The active differential equalizers presented in this paper have an outstanding feature of providing variable inclination and position of the positive or negative gain slopes, which can be easily adjusted to meet with various stringent requirements for frequency and temperature compensation in microwave and optical systems.

L-band SiGe HBT active differential equalizers with variable inclination and position of the positive or negative gain slopes

A dual-band 90-degree SiGe HBT active phase shifter using band-pass and band-stop designs is presented in this paper. The active phase shifter employs differential configuration and has band-pass and band-stop filters in the load circuit. By switching two output ports of the differential amplifier, 90-degree phase shifting has been realized at dual bands. The implemented dual-band active phase shifter using 0.35 micron SiGe HBT has achieved a gain of 9.3 dB and a phase shift of 95 degrees at 0.74 GHz as well as a gain of 8.9 dB and a phase shift of 98 degrees at 0.88 GHz. This is the first time to present a dual-band active phase shifter using band-pass and band-stop designs.

A dual-band 90-degree SiGe HBT active phase shifter using band-pass and band-stop designs

L-band SiGe HBT active differential equalizers with variable, positive or negative gain slopes have been designed and fabricated for frequency and temperature compensation of microwave and optical systems. The active equalizer employs varactor-tuned base bias circuits for variable and positive gain slopes or varactor-tuned collector bias circuits for variable and negative gain slopes. The implemented active equalizers have achieved positive gain slopes of +88 to +121dB/GHz across 0.5 to 1GHz as well as negative gain slopes of -17 to -46dB/GHz over 0.1 to 0.8GHz. The active differential equalizers presented in this paper have an outstanding feature of showing abrupt gain slopes with the use of bandstop performances, which can be useful for frequency and temperature compensation with narrowband but abrupt gain slopes.

L-band SiGe HBT active differential equalizers with varactor-tuned bias circuits for variable, positive or negative gain slopes

L-band SiGe HBT active differential equalizers with variable positive or negative gain slopes have been designed and fabricated for frequency and temperature compensation of microwave and optical systems. The active equalizer employs series/parallel LC resonator-loaded bridged-T attenuators in the feedback path of the differential amplifier to achieve high gain and variable positive or negative gain slopes at L-band. The implemented active equalizer employing a series LC resonator has achieved positive gain slopes of +60.3 to +110dB/GHz across 0.2 to 0.6GHz. Moreover, the implemented active equalizer using a parallel LC resonator has achieved negative gain slopes of −63.5 to −38.9dB/GHz over 0.4 to 0.8GHz. The active differential equalizers presented in this paper have an outstanding feature of providing variable positive or negative gain slopes, which can be easily adjusted to meet with various stringent requirements for frequency and temperature compensation in microwave and optical systems.

L-band SiGe HBT active differential equalizers providing variable positive or negative gain slopes

An L-band SiGe HBT active differential equalizer with variable positive/negative gain slopes has been designed, fabricated and performed. The active equalizer employs parallel RC circuits in the feedback and load circuits of the differential amplifier to achieve positive/negative gain slopes simultaneously. The implemented active equalizer has achieved positive gain slopes of 0 to +18dB/GHz as well as negative gain slopes of −13 to 0dB/GHz across 0.1 to 1GHz. The active differential equalizer presented in this paper has an outstanding feature of providing both positive and negative gain slopes coincidently from a single circuit, which can be easily employed in the microwave and optical systems with various requirements for frequency and temperature compensations.

Hiroaki Takagi

Papers

L-band SiGe HBT active differential equalizers with variable inclination and position of the positive or negative gain slopes

A dual-band 90-degree SiGe HBT active phase shifter using band-pass and band-stop designs

L-band SiGe HBT active differential equalizers with varactor-tuned bias circuits for variable, positive or negative gain slopes

L-band SiGe HBT active differential equalizers providing variable positive or negative gain slopes

An L-band SiGe HBT active differential equalizer with variable positive/negative gain slopes using parallel RC circuits