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This paper proposes a novel wideband 90${}^{\circ }$ phase shifter, which comprises a radial stub, a uniform transmission line, and a weak coupled-line (coupling coefficient $\mathrm{\text{C}}\ge 12.7$ dB). The circuit configuration and theoretical analysis equations of the phase shifter are presented. Results demonstrate that the bandwidth (BW) with acceptable phase deviation can be obviously improved by increasing the spanning angle of the radial-stub and the coupling strength of the coupled-line. For return loss better than 10 dB, insertion loss less than 1.05 dB, and phase deviation of $\pm$ 8.5${}^{\circ }$, the fabricated microstrip single-layer phase shifter exhibits BW of 118% from 0.65 GHz to 2.51 GHz. Compared with existing structures, the proposed phase shifter not only has the largest BW but also features simple structure, low-cost, convenient installation, and good portability.

In this paper, a wideband full-360^o phase shifter with 6 bits of accuracy has been designed and simulated with minimal root mean square (RMS) phase error. The proposed phase shifter deployed a feed forward path including a frequency-to-voltage converter (FVC) to minimize the mismatch in quadrature generation to eventually reduce the RMS phase error for S-band (2–4GHz) applications. The designed phase shifter in 180nm CMOS technology achieves an RMS phase error in the range of 0.607–1.18^∘ with $-50$dBm input signal over 2–4GHz frequency band. With lower input signal of $-75$dBm, the RMS phase error is 0.621–1.34^∘ for 2–4GHz input frequency. The proposed phase shifter shows an RMS amplitude error less than 0.41dB over 2–4GHz frequency. The 1-dB compression point ($P_{-1\mathrm{\text{dB}},\mathrm{\text{CP}}}$) of the proposed phase shifter is $-23$dBm. The proposed wideband phase shifter draws 32 mA from 1.8 supply voltage. It occupies an active area of only 0.025mm², due to active design without any inductor.

In traditional phased-array T/R modules, front-end modules such as limiter, low-noise amplifier (LNA) and RF switch are generally implemented by independent devices, with low integration and high cost. This paper realizes the integration of all receiver functional modules in the 0.13$\mu$m CMOS SOI process, including RF switch, LNA with limiter, 6-bit digital controlled attenuator and phase shifter, and drive amplifier. The LNA integrates a limiting function, which can suffer 2W continuous wave. Fast charge–discharge circuit is applied to the low insertion loss RF switch, which greatly reduces the switching time. The phase shifter adopts a double balanced switch used for 180^∘ phase shift, which significantly reduces the phase error. The measured channel gain is about 28dB with an NF about 2.3dB and an IP1 dB above $-$14dBm. The state error of attenuator is less than $+∕-0.6$dB with step error less than $+∕-0.3$dB. The RMS phase error of phase shifter is less than 1.8 degrees. The fully integrated transceiver IC occupies an area of $5\times 5.6$mm². This receiver draws only 128mA with a 3.3V power supply.

First-order allpass filters are analog filters with a unit magnitude response, but they change the phase shift between input and output signals at various frequencies. This paper presents the transadmittance-mode first-order allpass filters based on the modified current-controlled current differencing transconductance amplifier (M-CCCDTA). The proposed filters utilize a single M-CCCDTA and a grounded capacitor with no external resistors, making them well suited for implementation in an integrated circuit. The gain and phase response of the proposed filters can be adjusted electronically and separately. Also, the high output impedance of the proposed filters at both the input voltage node and the output current node makes cascading easy without the need for buffer devices. A quadrature sinusoidal oscillator based on the proposed first-order allpass filter has been designed as an example of an application. The PSpice simulation and actual experiments are utilized to validate the functionality of the proposed filters. The simulation and experimental results are consistent with the idea of anticipation.