## 1 Introduction  
An RF transceiver integrated circuit operating in the MedRadio band is widely employed for biomedical devices and sensors, as the wireless communication is essentially needed between the implanted or body-worn medical devices and outside controllers. The wireless connectivity for the biomedical devices is used to exchange the diagnostic and therapeutic data. Its non-invasiveness significantly improves the patient's comfortability by avoiding unnecessary painful surgical operations. The MedRadio band was assigned in 2009 [1], in the frequency band of 401-406 MHz providing a total 5 MHz of contiguous spectrum on a secondary and non-interference basis. The MedRadio rule was amended later in 2011 to allow networking of the devices and controllers and referred to as a medical micropower network (MMN) [2]. Since then, numerous implanted and wearable medical devices equipped with the MedRadio RF transceiver have been reported in literature, such as a wireless bio-signal monitoring system [3], an implanted cardiac defibrillator [4], an implanted pacemaker [5], an intraocular pressure monitoring system [6], physiological state monitoring prosthetic teeth [7; 8], wireless position sensing system in total hip replacement surgery [9], capsule endoscopy [10; 11], and so on. The RF communication channel of the MedRadio is accessed on a shared or secondary basis. Hence, they must be robust to interferers coming from nearby other authorized primary users [12]. For mitigating the interferences, system-level techniques, such as error detection and correction via proper channel-coding, listen-before-talk (LBT), and re-transmission via a frequency monitoring and classification process, are widely employed [1]. Yet, even though the system-level interference mitigation techniques are employed, additional circuit-level techniques are still needed in the RF transceiver design to improve the overall interference resilience. Unfortunately, however, most previous MedRadio RF integrated circuits, either transceivers [4; 5; 12; 13] or receivers [14; 15; 16; 17], did not address those issues nor present proper circuit designs for its mitigation. [PERSON] et al. [12] and [PERSON] et al. [14] indeed mentioned the in-band interference issue and described the adjacent channel rejection (ACR) and the third-order intercept power (IIP3) performances. However, their studies were still limited only to the in-band interference situation and cannot be generalized to the out-of-band interference situation. It is also interesting to note that [PERSON] et al. [18] addressed the very-high frequency (VHF) band interference issue in their dual-band RF receiver and demonstrated a blocker tolerance level of \(-45\) dBm for the MedRadio receiver against the VHF body-channel communication interference. However, their result was also limited to the VHF-band single-tone interference issue and not applicable to the UHF-band multi-tone interference issue. It is also worth noting that non-conventional signal modulation techniques can be also effective for the interference resilience improvement. Novel approaches such as the two-tone modulation [19] and the spread-spectrum modulation [20] were proven effective in 900 MHz transceivers. Yet, they were only applicable to the on-off keying (OOK) modulation and not to the constant-envelope modulation that is more widely adopted by MedRadio devices. The modern UHF and VHF bands are crowded with a variety of multi-tone signals. They always can be seen as unwanted strong interferers to the MedRadio biomedical devices and sensors. For example, the fifth-generation new radio (5G NR) band encompasses 600-800 MHz UHF band in its frequency range 1 (FR1) band. Additionally, digital broadcasting standards such as the advanced television systems committee (ATSC) of the United States and Korea [21], the digital video broadcasting (DVB) of Europe [22], and the intelligent service digital broadcasting (ISDB) of Japan [23] are serviced in the VHF band of 54-216 MHz and UHF band of 470-860 MHz.