Input Matching Performance Research Articles

Analysis and design of a 10–20 GHz simultaneous noise and input matching low‐noise amplifier via frequency‐dependent negative feedbacks

This letter presents a novel method to implement a 10–20 GHz low-noise amplifier (LNA) with simultaneous noise and input matching performance. That is, the Mille effect caused by the gate-drain parasitic capacitance Cgd is eliminated by converting the succeeding-stage impedance into the required load using frequency-dependent negative feedbacks and a π-type network. The corresponding analytical equation is also derived for the first time. To verify the feasibility, the circuit is fabricated via a 0.15-μm GaAs p-HEMT process with a compact size of 0.9×1.9 mm2. The measured results show that the proposed LNA features a peak gain of 26.1 dB, a minimum noise figure of 1.08 dB, and an input return loss of less than −15.8 dB.

A CMOS Vector-Sum Phase Shifter for 5G mm-Wave Application

This paper presents a wideband CMOS vector-sum phase shifter (VSPS) targeting the n260 band of 5G communication. A differential quadrature generator is implemented using a Marchand balun and two 90° coupled-line couplers to improve robustness to process and temperature variations. The quadrature vector signals are combined by a following vector modulator that adopts a double Gilbert-cell topology. The linearity and input-matching performance are enhanced at the expense of extra DC consumption by stacking a current source with high bias. The measurement shows that the VSPS provides a continuous 360° phase shift with an average insertion loss of 16.3 dB at 37 GHz. The root-mean-square (RMS) amplitude and phase errors maintain less than 1.5 dB and 4.9°, respectively, from 30.9 GHz to 41.7 GHz. The input-referred 1-dB compression point is 5.7 dBm at 38 GHz. It is also demonstrated by 484-state measurement that the phase and amplitude can be adjusted in a fine resolution.

A Wideband Differential Linear Low-Noise Transconductance Amplifier With Active-Combiner Feedback in Complementary MGTR Configurations

A wideband differential linear low-noise transconductance amplifier (LNTA) is proposed for SAW-less applications. An active combiner provides a dual-loop feedback for wideband matching with power efficiency. Operating as an auxiliary common source (CS) stage, complementary multi-gated transistor (MGTR) configurations are employed to compensate for the second- and third-order nonlinearity of the main CS stage, improving small-signal linearity. Large-signal linearity is also enhanced due to Class AB configurations. Additionally, the push-pull operation of the main CS stage and the auxiliary CS stage preserves good large-signal input matching performance. Implemented in a 0.18-μm CMOS process, the measured LNTA chip provides a minimum noise figure (NF) of 2.5 dB, and a maximum transconductance value of 76.7 mS from 0.1 to 3.1 GHz. On average, an input 1-dB compression point (IP1 dB) of 2.3 dBm and an input third-order intercept point (IIP3) of 17.8 dBm are obtained, respectively. The blocker NF is 4.0 dB under a 0 dBm blocker injection while the S <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">11</sub> <; -10 dB is maintained even with the blocker input of -3.1 dBm. The LNTA core only draws 13.3 mA from a 1.8 V supply.

Circular Conformal Array Antenna With Omnidirectional and Beamsteering Capabilities for 5G Communications in the 3.5-GHz Range [Wireless Corner

A circular conformal array antenna (CAA) with beamsteering capabilities as well as omnidirectional performance at 3.5 GHz (S-band) is presented. The single radiating elements are formed by double-stacked microstrip patches placed on the planar faces of an octagonal holding structure fabricated with a 3D printer. An eight-way tunable feeding network (TFN) is designed, manufactured, and integrated into the conformal structure to excite the array elements. Novel tunable T-junctions (TTs) based on p-i-n diodes are proposed to form the TFN in microstrip technology. This novel T-junction allows a splitting configuration with uniform distribution to the two output ports or a switching mode to deliver the signal to either output port. In all T-junction operation modes, good input matching performance is achieved. The TFN network is integrated into the conformal antenna and digitally controlled by a microcontroller Arduino MEGA. A total of 29 states grouped in six modes with a global matching bandwidth of 17.2% can be selected. The omnidirectional radiation and beamsteered directional patterns (covering 360°) can be electronically tuned. The proposed antenna is suitable for future 5G terrestrial communications in the 3.5-GHz International Mobile Telecommunication (IMT) range, the primary candidate band for the first 5G networks.

A Continuously Tunable Unequal Power Divider With Wide Tuning Range of Dividing Ratio

In this letter, a dividing ratio continuously tunable power divider with a wide tuning range is presented. A pair of tunable shunt stub is utilized to achieve different power dividing ratios and good input matching performance. By varying the loaded capacitance of the tunable stubs, a continuous tuning range from 1:1 to arbitrary dividing ratio can be achieved theoretically. For demonstration, a prototype circuit with the dividing ratio from 1:2 to 1:100 is designed and fabricated. Good agreement can be observed between the measured results and simulated results.

Sierpinski monopole antenna with controlled bandspacing and input impedance

A novel configuration of the Sierpinski triangular gasket antenna is proposed. A quasi-log-periodic performance was achieved for the operating bands of GSM, DECT and WLAN by using a new band spacing control technique. This design enhances the input matching performance to well over –10 dB with a 50 Ω feed.