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This paper aims to present a low-cost, edge-fed, windmill-shaped, notch-band eliminator, circular monopole antenna which is practically loaded with a complementary split ring resonator (CSRR) in the middle of the radiating conductor and also uses a partial ground to obtain wide-band performance.

To compensate for the reduced value of gain and reflection coefficient because of the full (complete) ground plane at the bottom of the substrate, the antenna is further loaded with a partial ground and a CSRR. The reduction in the length of ground near the feed line improves the impedance bandwidth, and introduced CSRR results in improved gain with an additional resonance spike. This results in a peak gain 3.895dBi at the designed frequency 2.45 GHz. The extending of three arms in the circular patch not only led to an increase of peak gain by 4.044dBi but also eliminated the notch band and improved the fractional bandwidth 1.65–2.92 GHz.

The work reports a –10dB bandwidth from 1.63 GHz to 2.91 GHz, which covers traditional coverage applications and new specific uses applications such as narrow LTE bands for future internet of things (NB-IoT) machine-to-machine communications 1.8/1.9/2.1/2.3/2.5/2.6 GHz, industry, automation and business-critical cases (2.1/2.3/2.6 GHz), industrial, society and medical applications such as Wi-MAX (3.5 GHz), Wi-Fi3 (2.45 GHz), GSM (1.9 GHz), public safety band, Bluetooth (2.40–2.485 GHz), Zigbee (2.40–2.48Ghz), industrial scientific medical (ISM) band (2.4–2.5 GHz), WCDMA (1.9, 2.1 GHz), 3 G (2.1 GHz), 4 G LTE (2.1–2.5 GHz) and other personal communication services applications. The estimated RLC electrical equivalent circuit is also presented at the end.

Because of full coverage of Bluetooth, Zigbee, WiFi3 and ISM band, the proposed fabricated antenna is suitable for low power, low data rate and wireless/wired short-range IoT-enabled medical applications.

The antenna is fabricated on a piece (66.4 mm × 66.4 mm × 1.6 mm) of low-cost low profile FR-4 epoxy substrate (0.54 λ_g × 0.54 λ_g) with a dielectric constant of 4.4, a loss tangent of 0.02 and a thickness of 1.6 mm. The antenna reflection coefficient, impedance and VSWR are tested on the Keysight technology (N9917A) vector network analyzer, and the radiation pattern is measured in an anechoic chamber.

Farmer producer organisations (FPOs) are considered as a strategy to improve the livelihoods of small farmers through economies of scale by providing collective strength to farmers for improved access to production technology, value-addition services, high-quality inputs and marketing services for improving their incomes. This study investigates the impact of FPO membership on organic farming household's income in Northeast India.

This study uses field survey data collected from all four districts of Sikkim. Primary data were obtained from a survey of 560 organic farming households, 280 of which are FPO members and the rest 280 are non-members. Propensity score matching (PSM) is used to estimate the impact of FPO membership on net returns, return on investment (ROI) and profit margin.

Results show that the FPO members had, on average, Rs. 7,254–8,133 higher annual net returns, 4.6–4.8% higher ROI and 8–8.4% higher profit margin than the non-members. The findings confirm that FPO membership has a positive and significant impact on net returns, return on investment and profit margin. Also, heterogeneity analysis indicates that FPO membership has larger positive impact on relatively bigger farmers and female-headed households.

As the study was based on a cross-sectional survey, the findings may be subjected to some limitations.

This study is based on a novel data set, collected specifically to examine the economic impact of FPO membership on organic farming in India.

The peer review history for this article is available at: https://publons.com/publon/10.1108/IJSE-06-2023-0451