Tx Band Research Articles

A wideband combined LNA‐filter in 22 nm FDSOI technology for satellite phased arrays

AbstractThis article introduces a new, low cost and complexity, wideband Ku/K‐band combined low‐noise amplifier (LNA) Filter designed for large satellite phased array systems in advanced 22 nm Fully Depleted Silicon on Insulator Technology. The LNA achieves the required 20 dB gain through a two‐stage configuration using the cascode configuration. To effectively reject the transmitter (TX) signal, the LNA integrates 4 distributed parallel LC notch filters. Measured IP1dB at 29 GHz (TX band) demonstrates a 25 dB increase compared to IP1dB at 19 GHz (RX Band), with a remarkable 15 dB enhancement over the LNA without the filter. The 1‐dB gain bandwidth spans from 16 to 21 GHz, representing a 27% fractional bandwidth. Over the entire bandwidth, input/output return losses exceed 10 dB, maintaining a low noise figure (NF) of less than 3.5 dB. Inclusion of two filters at the input and middle of the first stage results in approximately 0.6 dB of increase in NF when compared to the LNA without the filter.

A Four-Port Dual-Band Dual-Polarized Antenna for Ku-Band Satellite Communications

This paper presents the development of a four-port dual-band dual-polarized antenna for transmitting/receiving (Tx/Rx) applications in Ku-band satellite communications. The antenna consists of two antenna elements sharing a common radiating aperture, a low-band element formed by an L-probe proximity-fed square-ring radiator for operation at the Rx band of 10.7–12.75 GHz, and a high-band element realized by a stacked-patch radiator for operation at the Tx band of 13.75–14.5 GHz. Within a compact multilayer structure, the antenna achieves wide dual-band operation, with each band having the ability to simultaneously operate with dual polarization. An antenna prototype is fabricated and tested to verify its performance. The experimental results show that the proposed antenna achieves an impedance bandwidth of 9.28–12.96 GHz (13.21–15.32 GHz), an isolation value between two orthogonal polarizations of 12 dB (12.4 dB), and a peak gain of 6.63 dBi (5.42 diBi) at the low band (high band). Tx/Rx isolation of more than 14 dB is achieved in both the Rx band and Tx band.

Compact dual-band rectangular T E10 mode to circular TM01 mode converter for telemetry/telecommand applications in satellite communication: design, equivalent circuit modeling, mode level measurement technique and 3d printed manufacturing

In this study, the design of a dual-band mode converter, which provides transition from rectangular waveguide T E10 mode to circular waveguide TM01 mode and operates simultaneously in telemetry/telecommand (TT&C) frequencies, is presented along with its equivalent circuit and a mode level measurement technique. This dual-band converter is designed to uniformly excite TT&C slot antennas used in satellite communication with symmetric circular TM01 mode. The structure can work as a transceiver due to having one common rectangular waveguide feed. As a Ku-band application, a converter giving high purity TM01 mode at circular waveguide at 11.75 GHz/TX and 13.75 GHz/RX center frequencies is designed and manufactured with 3D printing technology. Approximate equivalent circuit models of the designed structure are extracted by using lumped elements from simulated S-parameter results. In addition, a measurement technique to detect the normalized power levels of different propagation modes in dual-band mode converter is applied on the manufactured structures to obtain transmission levels of circular TM01 mode and suppression levels of circular T E11 mode. It is revealed from the measurement results that while the designed structure gives more than 17.5 dB return loss and suppression of T E11 mode, and less than 0.6 dB insertion loss of TM01 mode within 500 MHz bandwidth at TX band, it gives more than 23 dB return loss and suppression of T E11 mode, and less than 0.3 dB insertion loss of T M01 mode within 900 MHz bandwidth at RX band.

Dual-Band Combined-Aperture Variable Inclination Continuous Transverse Stub Antenna With Consistent Beam Direction

This article presents a Tx/Rx dual-band combined-aperture variable inclination continuous transverse stub (VICTS) antenna for low-earth-orbit (LEO) satellite-on-the-move (SOTM) applications. The beam directions for the Tx and Rx bands are kept consistent during beam scanning, so that the antenna allows a duplex link. The topology of the combined-aperture VICTS antenna is derived from the requirement for consistent beam directions. Nonuniform slow wave structures (SWSs) are used to achieve the required phase difference and phase-changing rate (PCR) between the radiation slots in the two bands, while maximizing the antenna efficiency. Predeflection technique is applied to the radiation slots to reduce the gain drop at a wide beam scanning angle. A prototype operating at K- and Ka-bands is designed, fabricated, and measured. Experimental results show that the antenna has a consistent beam direction during scanning in the frequency ranges of 19–21 GHz (Rx band) and 29–31 GHz (Tx band). The maximum beam directions in Tx and Rx bands exceeds ±47° at a relative rotation angle of 40°, and the gain drop during the beam scanning is reduced within 2.3 and 3.5 dB.

Single Waveguide Feed Omnidirectional and Circularly Polarized Transceiver Waveguide Slot Antenna for Satellite Communication Applications

In this study, an omnidirectional and circularly polarized transceiver antenna, which can be used in simultaneous operations over transmit (TX) and receive (RX) channels for telemetry, tracking, and command (TTC) applications on the space segment of satellite communication, is proposed. The radiation and feed parts of the antenna consist of waveguide structures for high power necessity in transmit (telemetry) section. The radiation part includes two different sections of rotationally symmetric slotted arrays on circular waveguide, and radially outward metallic disks to improve omnidirectionality and circular polarization. The feed part contains a dual-band mod converter from rectangular TE10 mode to circular TM01 mode for symmetric field excitation over slots where the input of the converter is the standard rectangular waveguide. The design, simulation, and measurement results of the antenna are shown over a 3D printed prototype at Ku-band with center frequencies of 12 GHz and 14.25 GHz for TX and RX, respectively. With thin slots in telemetry section and thick slots in telecommand section, measured bandwidths for TX and RX frequencies are obtained approximately as 200 and 450 MHz, respectively. While TX band with maximum 3 dB gain variation over azimuth, maximum 3 dB axial ratio and minimum −3 dBi gain over 70° elevation beamwidth has relatively better performances at the expense of narrow bandwidth, RX band has maximum 3.5 dB gain variation over azimuth, maximum 4 dB axial ratio and minimum −6 dBi gain over 55° elevation beamwidth at the expense of wide bandwidth.

A 1–2-GHz Quadrature Balanced N-Path Receiver for Frequency Division Duplex Systems

The implementation of fully integrated frequency division duplexing (FDD) transceivers imposes many challenges, such as receiver (RX) desensitization by the transceiver (TX), reciprocal mixing, and sensitivity, to antenna voltage standing wave ratio (VSWR) variations. Here, we present the quadrature balanced N-path receiver (QBNR) architecture. The QBNR is composed of a quadrature hybrid and two identical mixers, presenting a short circuit and 50- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\Omega $ </tex-math></inline-formula> matching in the TX and RX bands, respectively. The TX power reflects at the mixers and reconstructs in-phase at the antenna, while the RX signal from the antenna can be reconstructed in phase at the baseband RX port. This architecture provides wideband FDD functionality while providing TX noise and local oscillator phase noise cancelation and antenna VSWR tunable compensation. Our implementation measurement results for an equalized configuration show more than 55-dB TX to RX isolation at frequencies of 1–2 GHz and for antenna VSWR of 2:1, with 3-dB TX loss and 4-dB RX loss, RX IP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1 dB</sub> of 5 dBm and TX IP <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">1 dB</sub> of 16 dBm, and receiver <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${B_{1\,\text {dB}}}$ </tex-math></inline-formula> of 10 dBm.

A Compact Diplexer Using Coupled π-CRLH Zeroth Resonators

ABSTRACT This paper presents a new diplexer design of a new-coupled composite right/left-handed (CRLH) resonator to serve the LTE applications. The realization of the diplexer is designed as coupled two zeroth order π-CRLH resonators to represent with zero electrical length and hence attaining a significant size reduction. The filters are designed to achieve a desired frequency bandwidth of 4% ∼16.7 Q-factor and ∼0.066 coupling coefficient at a centre frequency of 2.1 and 2.6 GHz with transmission zeros. The diplexer exhibits a rejection level of 15–20 dB while maintaining insertion loss of 1 dB for the Tx and Rx bands. The circuit design concepts are verified using equivalent circuit simulations, full electromagnetic simulations and experimental measurements. In conclusion, a good agreement is perceived between the measured and simulated data with size compactness of 30 × 60 mm2.

Harmonic Reflection Amplifier for Widespread Backscatter Internet-of-Things

The highly power-efficient backscattering communication scheme holds solid potentials to lead the Internet of Things technologies. However, the asymmetric radio frontend architectures that ensure cheap and pervasive communicating things and tags at one end of the link, overburden the other end of the link (“reader”) with complicated and expensive hardware. This turns out to prevent the integration of the technology in the wide spectrum of consumer electronic devices (e.g. RF smartphone platforms). By separating TX and RX frequency bands, the harmonic backscattering scheme drastically loosens the technological constraints toward integration. We propose here the use of a single tunnel diode to build a harmonic reflection amplifier (HRA), using the nonlinear behavior of the negative differential resistance region to both generate harmonics and amplify the signals. The circuit also behaves like a common backscatter, with the same-frequency backscattering modulation for operation with legacy readers. Operating below 150 mV, the HRA drains 144-μW dc power with a measured positive conversion gain of 18 dB.

Design and prototype manufacturing of a feed system for Ku‐band satellite communication by using 3D FDM/PLA printing and conductive paint technology

In this study, the realization of a Ku-band feed system for reflector antenna in satellite communication systems is presented using 3D printing and conductive paint methods. The system includes a corrugated conical horn antenna designed to operate at 10.5 to 18.5 GHz and an H-plane waveguide diplexer to operate at 10.7 to 12.75 GHz and 17.3 to 18.4 GHz in receive (RX) and transmit (TX) bands, respectively. In the manufacturing of the structures, fused deposition modeling (FDM) technology and polylactic acid material are processed for 3D printing, where nickel and silver conductive-based paints are used for coating purpose. The measurement results of the feed system are found to be in good agreement with simulations that the combined (nickel-coated antenna and silver-coated diplexer) structure has return loss of more than 10 dB and high gain performance of 12 to 17 dBi within the RX and TX bands of 10.7 to 12.75 GHz and 17.4 to 18.8 GHz, respectively; while rejection (isolation) level between TX and RX ports is higher than 60 dB. The complex structure containing several detailed shapes inside shows that this low-cost production technique as compared to high-cost CNC-based metallic production technology can be used for the prototype structures or proof-of-concept type studies of Ku-band systems.

Adaptive Cancellation of Digital Power Amplifier Receive Band Noise for FDD Transceivers

In frequency division duplex systems, spurious emission from transmitter (TX) can fall into receive band and lead to significant receiver desensitization. In this paper, a DSP-based solution that relies on a linear auxiliary receiver to cancel receive band noise (RxBN) from the received signal is demonstrated. This technique allows reduction of duplexer rejection requirements in the receiver band, and associated reduction of insertion loss in the TX band, thus resulting in high-power amplifier (PA) efficiency and small duplexer footprint. The PA architectures that inherently have high RxBN (such as envelope tracking and the digitally modulated PAs) can substantially benefit from this technique. Experimental results based on off-the-shelf system implementation are demonstrated using a digital PA, and more than 22 dB cancellation is achieved to reduce RxBN below thermal noise floor at 836 MHz with 45 MHz duplex spacing.

Adaptive Matching Transmitter With Dual-Band Antenna for Intraoral Tongue Drive System

The intraoral Tongue Drive System (iTDS) is a wireless assistive technology that detects users' voluntary tongue gestures, and converts them to user-defined commands, enabling them to access computers and navigate powered wheelchairs. In this paper, we presented a transmitter (Tx) with adaptive matching and three bands (27, 433, and 915MHz) to create a robust wireless link between iTDS and an external receiver (Rx) by addressing the effects of external RF interference and impedance variations of the Tx antenna in the dynamic mouth environment. The upper two Tx bands share a dual-band antenna, while the lower band drives a coil. The Tx antenna is simulated in a simplified human mouth model in HFSS as well as a real human head model. The adaptive triple-band Tx chip was fabricated in a 0.35-μm 4P2M standard CMOS process. The Tx chip and antenna have been characterized in a human subject as part of an iTDS prototype under open-and closed-mouth scenarios, which present the peak gain of -24.4 and -15.63 dBi at 433 and 915MHz, respectively. Two adaptive matching networks for these bands compensate variations of the Tx antenna impedance via a feedback mechanism. The measured S11 tuning range of the proposed network can cover up to 60 and 75 jΩ at 433 and 915MHz, respectively.

An FDD Wireless Diversity Receiver With Transmitter Leakage Cancellation in Transmit and Receive Bands

Antenna-coupling group delay limits the cancellation bandwidth of conventional self-interference cancellers (SICs), making it difficult to ensure isolation in both transmit (TX) and receive (RX) bands. Isolation over both bands is achieved in the dual-path receiver architecture proposed in this paper. The main path consists of a highly linear current-mode RX with a passive RF SIC. The auxiliary path implements a notch in the TX band followed by an adaptive digital equalizer whose output is used to suppress the TX noise leakage in the RX band. The main and auxiliary receiver prototypes, implemented in 28-nm CMOS technology, operate between 1 and 2 GHz, occupy an area of 0.51 and 0.12 mm2, and have a power dissipation of 32–40 and 26–64 mW, respectively. The stand-alone RX has a noise figure (NF) of 4–5 dB and an out-of-band IIP3 of 18 dBm. Turning on the passive canceller results in an effective IIP3 of 25–29 dBm and a degradation of the NF of less than 0.8 dB. Thanks to its high dynamic range, the auxiliary path suppresses the TX noise by >29 dB while degrading the RX NF by only 1 dB at 23-dBm TX output power.

Wide‐band duplexer based on electrical balance of hybrid transformer having two notches

A tunable transformer duplexer having two notches has been proposed and demonstrated for a broadband operation. The suggested duplexer using GaAs pseudomorphic high electron mobility transistor (pHEMT) technology shows isolations of over 55 dB at the transmitter (Tx) band and over 45 dB at the receiver (Rx) band across 145 MHz bandwidth. The insertion losses are −3.35 and −3.52 dB for the Tx band and the Rx band, respectively, for 500 MHz bandwidth. At all ports, the return losses are under −15 dB. The duplexer is tunable simply by tuning the four components. Although this broadband duplexer has a very compact size with tunable capability, its performance is comparable with the front end module integrated duplexer.

A WIDEBAND WAVEGUIDE DIPLEXER FOR THE EXTEND C-BAND ANTENNA SYSTEMS

A wideband diplexer for the extended C-band feed antenna system is proposed in this paper. The diplexer operates in the receiving band (Rx) 3.625-4.8 GHz and transmitting band (Tx) 5.85-7.025 GHz, which give 28% and 19% bandwidths at Rx and Tx bands, respectively. In order to cover such a broadband, a side coupling T-shaped junction and a corrugated low-pass filter scheme are adopted. The T-shaped junction and the filter are designed separately, and then combined for optimization. A prototype is fabricated and measured. Measured results show a good agreement with the calculated ones. The return loss is less than −21 dB, transmission loss less than 0.21 dB, Rx/Tx isolation better than 45 dB, and Tx/Rx isolation better than 70 dB.

Integrated Wideband Self-Interference Cancellation in the RF Domain for FDD and Full-Duplex Wireless

A fully integrated technique for wideband cancellation of transmitter (TX) self-interference (SI) in the RF domain is proposed for multiband frequency-division duplexing (FDD) and full-duplex (FD) wireless applications. Integrated wideband SI cancellation (SIC) in the RF domain is accomplished through: 1) a bank of tunable, reconfigurable second-order high-Q RF bandpass filters in the canceller that emulate the antenna interface’s isolation (essentially frequency-domain equalization in the RF domain) and 2) a linear $N$ -path $G_m$ - $C$ filter implementation with embedded variable attenuation and phase shifting. A 0.8–1.4 GHz receiver (RX) with the proposed wideband SIC circuits is implemented in a 65 nm CMOS process. In measurement, $>20\;\text{MHz}\;20\;\text{dB}$ cancellation bandwidth (BW) is achieved across frequency-selective antenna interfaces: 1) a custom-designed LTE-like 0.780/0.895 GHz duplexer with TX/RX isolation peak magnitude of 30 dB, peak group delay of 11 ns, and 7 dB magnitude variation across the TX band for FDD and 2) a 1.4 GHz antenna pair for FD wireless with TX/RX isolation peak magnitude of 32 dB, peak group delay of 9 ns, and 3 dB magnitude variation over 1.36–1.38 GHz. For FDD, SIC enhances the effective out-of-band (OOB) IIP3 and IIP2 to $+\text{25}\text{-}27\;\text{dBm}$ and $+90\;\text{dBm}$ , respectively (enhancements of 8–10 and 29 dB, respectively). For FD, SIC eliminates RX gain compression for as high as $-8\;\text{dBm}$ of peak in-band (IB) SI, and enhances effective IB IIP3 and IIP2 by 22 and 58 dB.

Tunable Duplexer With Passive Feed-Forward Cancellation to Improve the RX-TX Isolation

The paper presents an approach that enables trading off the insertion loss versus isolation in the duplexer design. Specifically, the Insertion Loss (IL) of the duplexer filters is reduced by using low-order Bandpass Filters (BPF), while the transmitter (TX) to receiver (RX) isolation is improved using a feed-forward, passive, wideband, cancellation scheme. The proposed cancellation scheme is fully passive and hence the duplexer does not incur power consumption and noise penalties. The linearity of the proposed duplexer is very high limited only by the tunable passive components used in the design. A tunable duplexer prototype is demonstrated with TX-RX isolation better than 50 dB in both TX and RX bands (high band TX: 860-890 MHz, RX: 948-984 MHz; low band TX: 700-718 MHz, RX: 780-801 MHz). Tuning is achieved using digitally controlled switched capacitors with silicon on sapphire (SOS) switches resulting in high linearity.

An unbalanced-to-balanced diplexer based on substrate integrated waveguide cavity

A novel unbalanced-to-balanced diplexer based on a dual-mode substrate integrated waveguide SIW cavity is proposed and implemented. The diplexer is realized using one dual-mode cavity and two single-mode cavities. By properly choosing, feeding and coupling the cavity operating at the TE102 or TE201 mode, so as to not only provide capabilities to realize the desired unbalanced-to-balanced transmission within both Rx and Tx channels but also realize good differential-mode channel-to-channel isolation. To the author's knowledge, we present for the first time an unbalanced-to-balanced type diplexer based on the application of SIW. The proposed diplexer was successfully designed, simulated, and fabricated. Good agreement can be observed between simulated and measured performances in our letter. The measured in-band common-mode rejection is better than 33 dB for both channels. A minimum differential-mode isolation of about 50 dB across the Rx band and about 40 dB across the Tx band is also observed in the measurement. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:173-177, 2015.

A novel 3D cavity diplexer with compact size using LTCC technologies for V-band wireless communication systems

In this article, a novel concept of 3D integrated V-band diplexer, which permits the realization of compact size using a dual-mode cavity and four single-mode cavities, has been realized in low-temperature cofired ceramic technologies. The dual-mode cavity resonator acting as one resonator for both Rx and Tx filters is developed to generate two resonant modes TE102 and TE103 at the center frequency of Rx 56.5-58.5 GHz and Tx 64-66 GHz channels, separately. Meanwhile, this dual-mode cavity becomes the interconnect between Rx/Tx channels and help to realize good isolation without using conventional T-junction. In the measurement, each filter designed for Rx and Tx channels exhibits excellent performance. Channel-to-channel isolations better than 35 dB across the Rx band and better than 32.5 dB across the Tx band are also obtained. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:141-145, 2015.

Balanced RF Duplexer with Low Interference Using Hybrid BAW Resonators for LTE Application

A balanced RF duplexer with low interference in an extremely narrow bandgap is proposed. The Long-Term Evolution band-7 duplexer should be designed to prevent the co-existence problem with the WiFi band, whose fractional bandgap corresponds to only 0.7%. By implementing a hybrid bulk acoustic wave (BAW) structure, the temperature coefficient of frequency (TCF) value of the duplexer is successfully reduced and the suppressed interference for the narrow bandgap is performed. To achieve an RF duplexer with balanced Rx output topology, we also propose a novel balanced BAW Rx topology and RF circuit block. The novel balanced Rx filter is designed with both lattice- and ladder-type configurations to ensure excellent attenuation. The RF circuit block, which is located between the antenna and the Rx filter, is developed to simultaneously function as a balance-tounbalance transformer and a phase shift network. The size of the fabricated duplexer is as small as . The maximum insertion loss of the duplexer is as low as 2.4 dB in the Tx band, and the minimum attenuation in the WiFi band is as high as 36.8 dB. The TCF value is considerably lowered to .

Dual-Band Horn Array Design Using a Helical Exciter for Mobile Satellite Communication Terminals

A horn array antenna is proposed for dual-band and dual-polarization operation. The array is optimally designed to be used as a feeder in mobile satellite terminals with a hybrid antenna (HA) structure, but it can be also used independently as a phased array. The array has an oval-shaped rim to maximize the efficiency of the HA, and is composed of 20 horn elements in a hexagonal structure. The element has a horn radiator with a conical helix, which is placed inside the horn and excited by two ports for TX and RX at both ends. Therefore, the antenna can be simultaneously operational in the Ka-band TX and K-band RX frequency bands, using a compact structure providing left-hand circular polarization (LHCP) for TX and right-hand circular polarization (RHCP) for RX. The fabricated array is connected with active channel modules having 20 channels each for TX and RX, and it was experimented on within a beam scanning range of -5° to +5° in the azimuth and elevation directions using phase control of the ac tive channel module. The antenna has a minimum gain of 21.7 dBi over the TX band and 19.7 dBi over the RX band over the desired scan region. The maximum pointing error is about 0.32° and the pointing loss is approximately 1.3 dB. In addition to meeting the above RF requirements, the antenna is designed to meet environmental specifications such as wind loads as required for mobile terminals.