A Passive STAR Microwave Circuit for 1-3 GHz Self-Interference Cancellation

Silva, Udara De; Pulipati, Sravan; Venkatakrishnan, Satheesh Bojja; Bhardwaj, Shubhendu; Madanayake, Arjuna

doi:10.1109/mwscas48704.2020.9184595

Cited by 7 publications

(4 citation statements)

References 27 publications

(20 reference statements)

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“…To overcome the aforementioned challenge, a lowprofile aperture-in-aperture (AiA) realization is investigated, considering 3 classes of antennas: a) ultra-wideband (UWB) tightly coupled arrays (TCDAs) [91], [92] [93]- [96], b) low profile planar circular monopole [97], [98] [99]- [101], and c) UWB patches [102], [103]. [104], [105].…”

Section: B Compact Wideband Aperture In Aperture Antenna Arraysmentioning

confidence: 99%

Cellular Wireless Networks in the Upper Mid-Band

Kang,

Mezzavilla,

Rangan

et al. 2024

IEEE Open J. Commun. Soc.

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The upper mid-band -approximately from 7 to 24 GHz -has recently attracted considerable interest for new cellular services. This frequency range has vastly more spectrum than the highly congested bands below 7 GHz while offering more favorable propagation and coverage than the millimeter wave (mmWave) frequencies. In this regard, the upper mid-band has the potential to provide a powerful and complementary frequency range that balances coverage and capacity. Realizing cellular networks that exploit the full range of these bands, however, presents significant technical challenges. Most importantly, spectrum will likely need to be shared with incumbents including communication satellites, military RADAR, and radio astronomy. Also, the upper mid-band is simply a vast frequency range. Due to this wide bandwidth, combined with the directional nature of transmission and intermittent occupancy of incumbents, cellular systems will likely need to be agile to sense and intelligently use large spatial and frequency degrees of freedom. This paper attempts to provide an initial assessment of the feasibility and potential gains of such adaptive wideband cellular systems operating across the upper mid-band. The study includes: (1) a detailed ray tracing simulation to assess potential gains of multi-band systems in a representative dense urban environment and illustrate the value of a wideband system with dynamic frequency selectivity; (2) an evaluation of potential cross-interference between satellites and terrestrial cellular services and interference nulling to reduce that interference; and (3) design and evaluation of a compact multi-band antenna array structure. Leveraging these preliminary results, we identify potential future research directions to realize next-generation systems in these frequencies.

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Section: B Compact Wideband Aperture In Aperture Antenna Arraysmentioning

confidence: 99%

Cellular Wireless Networks in the Upper Mid-Band

Kang,

Mezzavilla,

Rangan

et al. 2024

IEEE Open J. Commun. Soc.

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“…From a microwave circuit design standpoint, a circulator can be thought of as a 3-port device having scattering (S-) parameters given by (1), and (2) for ideal and real-world cases respectively, where |γ | ≤ 1 represents small imperfections due to impedance mismatch/variations [23].…”

Section: Proposed Ferrite-based 2-circulator Star Front-endmentioning

confidence: 99%

STAR Front-End Using Two Circulators in a Differential Connection

Zhao,

De Silva,

Venkatakrishnan

et al. 2024

IEEE J. Microw.

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In-band full duplex (IBFD) communication systems have attracted much interest due to their ability to double the spectrum efficiency by simultaneously transmitting and receiving (STAR) over the same bandwidth. Modern communication technologies have to adapt to be able to meet the ongoing high demand capacity over existing radio channels. This paper proposes a system-level approach based on physical symmetry to improve the electromagnetic performance of a 3-port circulator. A system-level design consisting of two matched circulators connected in a differential configuration is proposed to cancel out residual RF scattering and leakage that causes self-interference in a STAR front-end. The method is validated using a custom designed microwave circulator based on microstrip technology, which forms a building block that operates in the 3-8 GHz band with 20 dB isolation. The proposed RF front-end operates within an extended band of 3-8 GHz while simultaneously exhibiting improvement in isolation by about 10 dB (isolation 30 ± 4 dB) between the transmitter and the receiver ports of the STAR system.

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“…The most significant drawback of this approach is the loss of Tx signal caused by the component's internal leakage. When there is no circulator involved, other types of monostatic STAR implementations can achieve an isolation level of up to 55 dB [20]. For instance, by using an electrical duplex to substitute a circulator, these systems can manage to attain an isolation level of 60 dB across 26 MHz, as seen in [29].…”

Section: Comparison With Other State-of-art Star Systemsmentioning

confidence: 99%

“…Even though, an acceptable isolation is achieved across a wide bandwidth, however, half of the Tx signal is lost in the process of creating the equivalent leaking signal for cancellation. Similarly, the circulator-free design accomplished with a 180 • coupler and power splitters presented in [20], results in a loss of half the Tx power. In [21], a two-point SIC system is presented, which contributes to reducing the interference between the Tx and Rx in FD radios.…”

Section: Introductionmentioning

confidence: 99%

Improving Isolation in Monostatic Simultaneous Transmit and Receive Systems Using a Quasi-Symmetrical Self-Interference Cancellation Architecture

et al. 2023

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For simultaneous transmit (Tx) and receive (Rx), it is a common practice, with monostatic full duplex (FD) systems, to use a single antenna and a circulator to provide isolation between the transmit and receive radio chains. However, most circulators currently on the market are designed to provide 12 to 20 dB of Tx/Rx port isolation, which is not sufficient for full duplex (FD) microwave communication. In fact, it is necessary to provide at least >30 dB of isolation to prevent the receiver desensitization that is caused by the leakage of high-power transmit signals. For this reason, practical simultaneous transmit and receive (STAR) systems require additional cancellation stages. In this paper, we present a novel STAR system that incorporates two circulators, a hybrid coupler, and a self-interference cancellation (SIC) circuit, based on a Finite Impulse Response (FIR) topology. Our design achieves an average Tx/Rx port isolation of ∼37 dB over a 25 MHz bandwidth (viz. 2.395-2.42 GHz) in simulation, with a minimum and maximum cancellations of 35 dB and 41 dB, respectively. A prototype was fabricated and tested showing good agreement with the simulations. All in all, the prototype achieved an average cancellation of 36 dB, with a cancellation range of 33 dB to 42 dB. INDEX TERMS Coupling signal, in-band full duplex (IBFD), simultaneous transmit and receive (STAR), self-interference cancellation (SIC).ELIAS A. ALWAN (Member, IEEE) was born in Aitou, Lebanon, in 1984. He received the B.E. degree (summa cum laude

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A Passive STAR Microwave Circuit for 1-3 GHz Self-Interference Cancellation

Cited by 7 publications

References 27 publications

Cellular Wireless Networks in the Upper Mid-Band

Cellular Wireless Networks in the Upper Mid-Band

STAR Front-End Using Two Circulators in a Differential Connection

Improving Isolation in Monostatic Simultaneous Transmit and Receive Systems Using a Quasi-Symmetrical Self-Interference Cancellation Architecture

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